Essential Oils

Balsam fir oil is steam-distilled from the needles of the boreal conifer that also gives Canada balsam, the clear resin held in blisters on its bark.

It is almost entirely monoterpenes, more than 96% of the oil ^{24Reference 24Pichette et al. · 2006In vitroComposition and antibacterial activity of Abies balsamea essential oil — in vitroView study →}. β-Pinene leads, with δ-3-carene and α-pinene behind it.

Native peoples across its range used the resin on cuts, sores, and boils. Needles and resin were heated on live coals and the smoke inhaled for colds, or used in sweat baths ^{27Reference 27MoermanMoerman, D. E. Native American Ethnobotany Database: Abies balsamea (L.) Mill. — ethnobotanical records. Botanical Research Institute of Texas. http://naeb.brit.org/uses/search/?string=Abies+balsameaView study →28Reference 28EarleEarle, C. J. (ed.). Abies balsamea — species account, ethnobotany and conservation status. The Gymnosperm Database. https://www.conifers.org/pi/Abies_balsamea.phpView study →}. The ground needles still fill scented pillows ^{28Reference 28EarleEarle, C. J. (ed.). Abies balsamea — species account, ethnobotany and conservation status. The Gymnosperm Database. https://www.conifers.org/pi/Abies_balsamea.phpView study →}.

The needle oil was active against Staphylococcus aureus in the laboratory, with a minimum inhibitory concentration of 56 µg/mL, and inactive against Escherichia coli ^{24Reference 24Pichette et al. · 2006In vitroComposition and antibacterial activity of Abies balsamea essential oil — in vitroView study →}.

The activity did not come from the main compounds. β-Pinene and δ-3-carene were inactive, while α-pinene and the minor sesquiterpenes β-caryophyllene and α-humulene were active ^{24Reference 24Pichette et al. · 2006In vitroComposition and antibacterial activity of Abies balsamea essential oil — in vitroView study →}.

The oil was also toxic to six tumour cell lines, but only at milligram-per-millilitre doses, and the effect traced to α-humulene ^{29Reference 29Legault et al. · 2003In vitroAntitumor activity of balsam fir oil: production of reactive oxygen species induced by alpha-humulene as possible mechanism of action — in vitroView study →}. No trial has tested the oil in people.

Caution: Conifer resins are recognised skin sensitisers, and oxidised fir oil is more sensitising than fresh oil. Keep the bottle sealed and cool, and dilute the oil before it touches skin. Use in pregnancy has not been researched.

Grand fir is a tall true fir of the Pacific Northwest, with flat, glossy needles lying in two neat rows along the twig. Its steam-distilled needle oil goes into aromatherapy blends ^{30Reference 30Czakert et al. · 2024RCTScenting serenity: influence of essential-oil vaporization on dental anxiety — a cluster-randomised, controlled, single-blinded study (AROMA_dent) — randomised controlled trialView study →}.

A comparison of seven fir oils placed grand fir with Siberian fir in a bornyl-acetate type ^{23Reference 23Ayupova et al. · 2025In vitroComparative phytochemical profiling of essential oils from selected Abies species and analysis of their antifungal and antiradical activity — in vitroView study →}. In the young shoots, though, β-pinene and camphene lead.

Coast Salish healers on Vancouver Island use the bark in decoctions for respiratory, digestive, and gynaecological complaints ^{31Reference 31Turner et al. · 1990ObservationalContemporary use of bark for medicine by two Salishan native elders of southeast Vancouver Island, Canada — ethnobotanical/observationalView study →}. A decoction of branches and cones is taken for respiratory ailments, and the pitch is made into a poultice for wounds, burns, and sore eyes ^{32Reference 32Howard et al. · 2000ReviewAbies grandis, grand fir — distribution, site characteristics, botanical description and other uses — species reviewView study →}.

The oil appears in one human trial, as one of eight oils in a “Forest Walk” scent vaporised in four dental practices. Across 486 patients, acute anxiety was slightly lower with scent, and the effect held up only in women and in patients with high trait anxiety ^{30Reference 30Czakert et al. · 2024RCTScenting serenity: influence of essential-oil vaporization on dental anxiety — a cluster-randomised, controlled, single-blinded study (AROMA_dent) — randomised controlled trialView study →}.

No study has tested grand fir oil on its own.

Caution: There is no toxicology data for any grand fir preparation. Conifer resins can cause contact allergy, and the oil is for inhaling or diluted use on the skin, not for swallowing. Pregnancy and breastfeeding have not been studied.

Subalpine fir is a narrow, spire-shaped fir of the western North American mountains, growing up to the treeline. Its needles yield an oil rich in limonene and bornyl acetate ^{33Reference 33Swor et al. · 2023Gymnosperms of Idaho: chemical compositions and enantiomeric distributions of essential oils of Abies lasiocarpa, Picea engelmannii, Pinus contorta, Pseudotsuga menziesii and Thuja plicata — essential-oil analysisView study →}.

The oil changes across the range. Coastal trees give a β-phellandrene oil, while Rocky Mountain trees give a limonene, camphene, and bornyl acetate oil ^{33Reference 33Swor et al. · 2023Gymnosperms of Idaho: chemical compositions and enantiomeric distributions of essential oils of Abies lasiocarpa, Picea engelmannii, Pinus contorta, Pseudotsuga menziesii and Thuja plicata — essential-oil analysisView study →}.

Its scent was put to use long before distillation. Pulverised needles served as a body and clothing perfume, and boughs were brought indoors for their aroma ^{34Reference 34Uchytil · 1991ReviewAbies lasiocarpa, subalpine fir — distribution, botanical description, elevation, associated species and other uses — species reviewView study →}.

The boiled resin was used as an antiseptic for wounds or drunk as a tea for colds, and the Shoshoni took a needle tea for colds ^{33Reference 33Swor et al. · 2023Gymnosperms of Idaho: chemical compositions and enantiomeric distributions of essential oils of Abies lasiocarpa, Picea engelmannii, Pinus contorta, Pseudotsuga menziesii and Thuja plicata — essential-oil analysisView study →34Reference 34Uchytil · 1991ReviewAbies lasiocarpa, subalpine fir — distribution, botanical description, elevation, associated species and other uses — species reviewView study →}.

The oil’s chemistry is well mapped, but no study has yet tested it for biological activity.

Caution: Aged resin is the main allergy risk. Abietic acid itself was not allergenic in testing, but its oxidation products, which build up as resin sits in air, were ^{35Reference 35Karlberg · 1988AnimalContact allergy to colophonyView study →}. The oil should not be swallowed, and pregnancy and breastfeeding have not been studied.

Siberian fir oil is distilled from the needles of a fir of Siberia and Kazakhstan. It is a bornyl acetate fir, with about 31% of the ester in one analysis ^{23Reference 23Ayupova et al. · 2025In vitroComparative phytochemical profiling of essential oils from selected Abies species and analysis of their antifungal and antiradical activity — in vitroView study →}.

Camphene, α-pinene, and δ-3-carene each add about 15%.

Siberian fir oil distilled with microwave heating inhibited Candida albicans by 82% in the laboratory, against 95% for the antifungal drug 5-flucytosine ^{23Reference 23Ayupova et al. · 2025In vitroComparative phytochemical profiling of essential oils from selected Abies species and analysis of their antifungal and antiradical activity — in vitroView study →}.

It was also one of the eight oils in the “Forest Walk” blend tested against dental anxiety ^{30Reference 30Czakert et al. · 2024RCTScenting serenity: influence of essential-oil vaporization on dental anxiety — a cluster-randomised, controlled, single-blinded study (AROMA_dent) — randomised controlled trialView study →}.

In a safety study, a dental gel made with the oil caused no visible changes on the skin of guinea pigs. The oil given by mouth to mice for four weeks caused only minimal changes ^{36Reference 36Noreikaitė et al. · 2017General toxicity and antifungal activity of a new dental gel with essential oil from Abies sibirica LView study →}.

Caution: Like other conifer oils, it is for inhaling or diluted use on the skin. Oxidised oil is more irritating than fresh, so keep it sealed and cool.

Yarrow oil is distilled from the flowering tops of a feathery-leaved meadow herb found across the Northern Hemisphere.

It is mostly an oxygenated monoterpene oil, led in one aromatherapy analysis by camphor, sabinene, 1,8-cineole, and α-pinene ^{39Reference 39Battaglia S · 2003The Complete Guide to Aromatherapy (2nd ed.)}.

Some yarrow oils are deep blue. The colour is chamazulene, which is not in the fresh plant. It forms during steam distillation from proazulenes such as achillicin ^{39Reference 39Battaglia S · 2003The Complete Guide to Aromatherapy (2nd ed.)}.

The herb is a classic of Western herbalism for wounds, bleeding, and the onset of fevers ^{37Reference 37A Modern Herbal (Grieve M) · 1931YarrowView study →}. Commission E approves it externally as a sitz bath or compress for skin inflammation and slow-healing wounds ^{41Reference 41Németh E · 2008ReviewBiological activities of yarrow species (Achillea spp.) — [review]View study →}.

In the laboratory, the oil inhibited Streptococcus pneumoniae, Clostridium perfringens, Candida albicans, and Mycobacterium smegmatis, and it scavenged free radicals ^{42Reference 42Candan F et al. · 2003In vitroAntioxidant and antimicrobial activity of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. — [in vitro]View study →}. No trial has tested the oil in people.

Quality varies. In a survey of 40 commercial yarrow samples, only half met European Pharmacopoeia standards ^{38Reference 38Benedek B et al. · 2008In vitroYarrow (Achillea millefolium L. s.l.): pharmaceutical quality of commercial samples — [in vitro]View study →}.

Caution: Yarrow can cause allergic contact dermatitis in people sensitive to the daisy family ^{43Reference 43Cosmetic Ingredient Review (Andersen FA · 2001ReviewFinal report on the safety assessment of Yarrow (Achillea millefolium) Extract — [review]View study →}. It is a traditional menstrual stimulant and is best avoided in pregnancy ^{41Reference 41Németh E · 2008ReviewBiological activities of yarrow species (Achillea spp.) — [review]View study →}.

Calamus oil is distilled from the pungent, spicy rhizome of a wetland plant of Asia and Europe. It has been used in pharmaceuticals and to flavour wines and liqueurs ^{45Reference 45Bertea CM et al et al. · 2005In vitroIdentification of an EcoRI restriction site for a rapid and precise determination of beta-asarone-free Acorus calamus cytotypes — in vitroView study →}.

The oil is led by β-asarone and α-asarone, and the amount depends on the type of plant.

Diploid plants hold about 2% oil with no or trace β-asarone. Triploids hold about 3%, with 5–19% of the oil as β-asarone. Tetraploids hold up to 6%, with 70–96% ^{44Reference 44Szczeblewski P et al. · 2022The role of centrifugal partition chromatography in the removal of β-asarone from Acorus calamus essential oil — analytical, Scientific reports, 12. https://pubmed.ncbi.nlm.nih.gov/36564541/View study →}.

In Ayurveda the rhizome is vacha, a herb for memory, speech, and clarity of mind. Western herbalism uses it in small doses as a warming digestive bitter.

The type of oil changes the result. A β-asarone-free oil relaxed gut muscle in spasm as well as an antihistamine did, while a β-asarone-rich oil had no such effect at the same concentration ^{47Reference 47Keller K et al et al. · 1985In vitroSpasmolytische wirkung des isoasaronfreien kalmus1 — in vitroView study →}.

The oil also killed bacteria and fungi in the laboratory ^{48Reference 48Joshi RK · 2016In vitroAcorus calamus Linn.: phytoconstituents and bactericidal property — in vitroView study →}. No trial has tested it in people.

Caution: The isolated compound β-asarone is genotoxic and causes liver and intestinal tumours in rodents ^{49Reference 49Cartus AT et al et al. · 2015In vitroHepatic metabolism of carcinogenic β-asarone — in vitroView study →50Reference 50Chellian R et al et al. · 2017ReviewPharmacology and toxicology of α- and β-Asarone: A review of preclinical evidence — reviewView study →}, and calamus is banned as a food additive in the United States.

The oil is also a moderate skin sensitiser and irritant. One assessment set safe levels of 0.13–0.78% for leave-on skin products ^{51Reference 51Desai et al. · 2025In vitroComprehensive in vitro safety assessment of Acorus calamus rhizome oil using OECD-compliant new approach methods: classification as a GHS category 1B sensitiser and category 2 irritantView study →}.

Calamus products sold online as hallucinogens caused 30 intoxications reported to the Swedish Poisons Information Centre, mostly prolonged vomiting ^{52Reference 52Björnstad K et al et al. · 2009Case reportBioanalytical investigation of asarone in connection with Acorus calamus oil intoxications — human case seriesView study →}. Avoid it in pregnancy and while breastfeeding.

Buchu oil is distilled from the small, leathery leaves of a shrub that grows wild only in the mountains of the Western Cape. The leaf and its oil smell strongly of blackcurrant ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →}.

It is a ketone oil. Its main compounds are isomenthone, menthone, and limonene, with diosphenol, a compound produced by no other genus ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →}.

Sulphur compounds such as 8-mercapto-p-menthan-3-one sit at low levels and carry much of the blackcurrant note ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →}.

The Khoi and San powdered the dried leaf, mixed it with fat, and rubbed it on the body as an anointment and perfume ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →}. As a medicine it was taken for the kidneys and bladder, and Europe adopted it as a urinary remedy in the nineteenth century ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →}.

Today the oil is mainly a blackcurrant flavouring, with FEMA GRAS status ^{54Reference 54Cohen SM et al. · 2020ReviewFEMA GRAS assessment of natural flavor complexes: mint, buchu, dill and caraway derived flavoring ingredients — reviewView study →}.

In the laboratory the oil relaxed guinea-pig gut muscle through a cyclic-AMP pathway and calcium-channel block ^{55Reference 55Lis-Balchin M et al. · 2001In vitroBuchu (Agathosma betulina and A. crenulata, Rutaceae) essential oils: their pharmacological action on guinea-pig ileum and antimicrobial activity on microorganisms — in vitro studyView study →}. Its antimicrobial activity was weak ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →55Reference 55Lis-Balchin M et al. · 2001In vitroBuchu (Agathosma betulina and A. crenulata, Rutaceae) essential oils: their pharmacological action on guinea-pig ileum and antimicrobial activity on microorganisms — in vitro studyView study →}. It also inhibited the diabetes-related enzymes PTP1B and DPP4 in enzyme tests ^{56Reference 56Adedirin O · 2026In vitroDual PTP1B/DPP4 inhibitory potential of Agathosma betulina, Cymbopogon citratus and Artemisia afra: structure-based modeling of phytochemical leads and essential oil bioassays — in vitro/in silico studyView study →}.

Caution: The oil carries pulegone, which the liver converts to the toxic menthofuran ^{57Reference 57Zárybnický T et al. · 2018ReviewHepatotoxicity of monoterpenes and sesquiterpenes — reviewView study →}. High doses of buchu oil harmed liver and uterine function in rats, so the oil is avoided in pregnancy ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →}.

EFSA classes the oil as a skin and eye irritant and a skin and respiratory sensitiser ^{58Reference 58Bampidis V et al. · 2022ReviewSafety and efficacy of a feed additive consisting of an essential oil from the leaves of Agathosma betulina/A. crenulata — reviewView study →}. A leaf infusion carries little pulegone, because pulegone does not dissolve in water ^{53Reference 53Brendler T · 2022ReviewBuchu (Agathosma betulina and A. crenulata): Rightfully Forgotten or Underutilized? — reviewView study →}.

Dill seed oil is distilled from the ripe fruit. It is a ketone and monoterpene oil, close to caraway in character, built almost entirely on carvone and limonene ^{59Reference 59Milenković et al. · 2024Chemical composition and bioactivity of dill seed (Anethum graveolens L.) essential oil from plants grown under shadingView study →}.

Dill herb oil, also called dill weed oil, is steam-distilled from the stalks and leaves before the seed ripens ^{60Reference 60EFSA Panel on Additives et al. · 2022Safety and efficacy of a feed additive consisting of an essential oil from the aerial parts of Anethum graveolens L. (dill herb oil) for use in dogs and cats (FEFANA asbl)View study →}. It keeps carvone and limonene but adds α-phellandrene and dill ether, which give it the fresh smell of the green herb.

The seed oil was active against several Candida species in the laboratory. As a 2% preparation it cleared vaginal Candida albicans faster in immunosuppressed mice ^{61Reference 61Zeng et al. · 2011In vitroIn vitro and in vivo activities of essential oil from the seed of Anethum graveolens L. against Candida sppView study →}. No trial has tested dill oil in people.

Caution: EFSA classes dill herb oil as a skin and eye irritant and a skin and respiratory sensitiser ^{60Reference 60EFSA Panel on Additives et al. · 2022Safety and efficacy of a feed additive consisting of an essential oil from the aerial parts of Anethum graveolens L. (dill herb oil) for use in dogs and cats (FEFANA asbl)View study →}. Myristicin, dillapiole, and apiole have been reported in some dill oils, though not in the commercial batches EFSA tested ^{60Reference 60EFSA Panel on Additives et al. · 2022Safety and efficacy of a feed additive consisting of an essential oil from the aerial parts of Anethum graveolens L. (dill herb oil) for use in dogs and cats (FEFANA asbl)View study →}. Apiole is an abortifacient, so apiole-rich dill oil is best avoided in pregnancy.

Angelica gives two oils. Both are monoterpene oils, but they are built differently. Its seeds and roots have long flavoured gin, vermouth, and liqueurs such as Chartreuse ^{62Reference 62Grieve · 1931A Modern Herbal — AngelicaView study →}.

Angelica root oil is distilled from the thick, fleshy root, which yields about 1% oil ^{62Reference 62Grieve · 1931A Modern Herbal — AngelicaView study →}. It spreads its weight across several monoterpenes. The musky macrocyclic lactones pentadecanolide and tridecanolide are present in smaller amounts ^{63Reference 63Battaglia · 2003The Complete Guide to Aromatherapy (2nd ed.)64Reference 64Arctander S · 1994Perfume and flavour materials of natural origin, Allured publishing, USA}.

Angelica seed oil is distilled from the ripe fruit. It is far simpler, a β-phellandrene oil with little else.

In the European herbal tradition the root is a warming carminative and digestive, and the seeds are the strongest part ^{62Reference 62Grieve · 1931A Modern Herbal — AngelicaView study →}.

Root oil delayed and shortened seizures in mice, though it also impaired movement at those doses ^{69Reference 69Pathak S et al. · 2010AnimalEvaluation of Antiseizure Activity of Essential Oil from Roots of Angelica archangelica Linn. in Mice — animal model (mouse)View study →}. It inhibited Clostridium difficile, Enterococcus faecalis, and Candida albicans in the laboratory, and had much weaker effects on the bifidobacteria and lactobacilli of a healthy gut ^{65Reference 65Fraternale D et al. · 2014In vitroEssential oil composition and antimicrobial activity of Angelica archangelica L. (Apiaceae) roots — in vitroView study →}.

Seed oils were toxic to pancreatic and breast cancer cells in culture ^{68Reference 68Sigurdsson S et al. · 2005In vitroThe cytotoxic effect of two chemotypes of essential oils from the fruits of Angelica archangelica L — in vitroView study →}. No trial has tested either oil in people.

Caution: The root contains linear furanocoumarins, which make skin burn in sunlight and are photo-genotoxic under UVA in the laboratory ^{70Reference 70Raquet N · 2014In vitroApplication of the equivalency factor concept to the phototoxicity and -genotoxicity of furocoumarin mixtures — in vitroView study →}. Do not apply angelica oil before sun exposure. Angelica is a traditional emmenagogue and is avoided in pregnancy ^{62Reference 62Grieve · 1931A Modern Herbal — AngelicaView study →}.

Rosewood oil is steam-distilled from the chipped heartwood of an evergreen Amazonian tree of the laurel family ^{72Reference 72Useful Tropical Plants (FernAniba rosaeodora Ducke — habit, habitat, range, harvest and uses — species databaseView study →}. In Brazil the tree is called pau-rosa, and its oil is rose-scented.

It is one of the purest alcohol oils. Heartwood oil is about 78–93% linalool ^{73Reference 73Maia et al. · 2009Database of the Amazon aromatic plants and their essential oils}. An oil from the leaves and thin branches of one western Pará population held 83.7% ^{71Reference 71Amazonas DR et al. · 2020Chemical and genotypic variations in Aniba rosaeodora — chemistryView study →}, and a leaf oil held 88.6% ^{74Reference 74Dos Santos ÉRQ et al. · 2018AnimalLinalool-rich essential oils from the Amazon display antidepressant-type effect in rodents — animal modelView study →}.

The rest is related monoterpenoids, among them α-terpineol, geraniol, and 1,8-cineole.

The name “rosewood” also belongs to the unrelated Dalbergia timbers of the pea family. They are a different plant and a different product.

Its sourcing is a real concern. Oil production has meant felling the whole tree, and heavy exploitation has made rosewood endangered.

Since 2010 its logs, sawn wood, and pure essential oil have been listed on CITES Appendix II, so international trade needs permits ^{75Reference 75CITES Secretariat · 2010Notification to the Parties NoView study →}. Leaf oil can be distilled without cutting the tree down ^{76Reference 76d’Acampora Zellner B et al. · 2006Leaf-derived extracts as an environmentally sustainable source of rosewood essential oil — chemistryView study →}. Ask whether an oil comes from cultivated trees or from leaves, and whether it carries CITES paperwork.

In Brazilian Amazonian folk medicine, rosewood is used for the nerves and valued as a sedative. Aromatherapists apply it to the skin for acne, dermatitis, and minor wounds, and inhale it for headaches, nervous tension, and nausea.

In mice, linalool-rich rosewood oil shortened the time to fall asleep and lengthened drug-induced sleep ^{77Reference 77de Almeida RN et al. · 2009AnimalRosewood oil induces sedation and inhibits compound action potential in rodents — animal modelView study →}. The leaf oil produced antidepressant-type effects in rats, which the authors attributed to linalool ^{74Reference 74Dos Santos ÉRQ et al. · 2018AnimalLinalool-rich essential oils from the Amazon display antidepressant-type effect in rodents — animal modelView study →}.

The oil also inhibits bacteria. It reduced injury and bacterial colonisation in mice and chicks infected with Salmonella when given as a preventive ^{78Reference 78Wang L et al. · 2024In vitroProtective effects and mechanisms of rosewood essential oil against Salmonella infection — in vitro and animal modelView study →}. No trial has tested rosewood oil on its own in people.

Caution: Rosewood is for the skin and inhalation, not for taking by mouth. Linalool oxidises in air to form potent skin sensitisers, and 7.0% of 5,773 Swedish patients with dermatitis were allergic to oxidised linalool ^{79Reference 79Sukakul T et al. · 2022ObservationalContact allergy to oxidized linalool and oxidized limonene: patch testing in consecutive patients — observationalView study →}. Keep the oil sealed, cool, and dark, dilute it to about 1–2%, and patch-test first.

Celery seed oil is steam-distilled from the ripe fruit ^{80Reference 80EFSA Panel on Additives et al. · 2024Safety and efficacy of a feed additive consisting of an essential oil obtained from the fruit of Apium graveolens L. (celery seed oil) for all animal species (FEFANA asbl) — regulatory opinion: composition and safety of celery seed oilView study →}. It is a limonene oil, but its smell comes from the phthalides, the compounds that make celery smell like celery.

Limonene leads at more than half the oil, with β-selinene next. Phthalides make up about a quarter, led by senkyunolide A and 3-n-butylphthalide ^{80Reference 80EFSA Panel on Additives et al. · 2024Safety and efficacy of a feed additive consisting of an essential oil obtained from the fruit of Apium graveolens L. (celery seed oil) for all animal species (FEFANA asbl) — regulatory opinion: composition and safety of celery seed oilView study →}.

The seed is a traditional remedy for gout, rheumatism, and fluid retention ^{81Reference 81Tan et al. · 2023Systematic reviewNeurological applications of celery (Apium graveolens): a scoping review — systematic reviewView study →}. Culpeper used the seed of smallage, the wild form, “to break and expel wind” ^{82Reference 82Culpeper et al. · 2015https://www.gutenberg.org/ebooks/49513View study →}.

Phthalides from the seed, including sedanolide, inhibited the COX-1 and COX-2 enzymes in the laboratory ^{83Reference 83Momin et al. · 2002In vitroAntioxidant, cyclooxygenase and topoisomerase inhibitory compounds from Apium graveolens Linn. seeds — in vitroView study →}. 3-n-Butylphthalide, first isolated from celery seed, is the basis of a synthetic stroke drug licensed in China ^{84Reference 84Abdoulaye et al. · 2016ReviewA review of recent advances in neuroprotective potential of 3-N-butylphthalide and its derivatives — reviewView study →}. That drug is not the oil, and no trial has tested celery seed oil in people.

Caution: EFSA classes the oil as a skin and eye irritant and a skin and respiratory sensitiser ^{80Reference 80EFSA Panel on Additives et al. · 2024Safety and efficacy of a feed additive consisting of an essential oil obtained from the fruit of Apium graveolens L. (celery seed oil) for all animal species (FEFANA asbl) — regulatory opinion: composition and safety of celery seed oilView study →}. Celery is a labelled food allergen in the EU ^{85Reference 85European Parliament et al. · 2011Regulation (EU) No 1169/2011 on the provision of food information to consumers, Annex II: substances or products causing allergies or intolerances, item 9, “Celery and products thereof” — regulation. https://www.legislation.gov.uk/eur/2011/1169/annex/IIView study →}. Medicinal doses have not been studied in pregnancy, and Culpeper wrote that smallage “provokes urine and women’s courses” ^{82Reference 82Culpeper et al. · 2015https://www.gutenberg.org/ebooks/49513View study →}.

Wormwood oil is distilled from the intensely bitter, silver-leaved herb that flavours absinthe and vermouth. The dried herb holds roughly 0.2–1.3% oil ^{86Reference 86Ghafoori et al. · 2014Study of effect of extraction conditions on the biochemical composition and antioxidant activity of Artemisia absinthium by HPLC and TLC87Reference 87Joshi · 2013In vitroVolatile composition and antimicrobial activity of the essential oil of Artemisia absinthium growing in the Western Ghats region of North West Karnataka, India — in vitroView study →}.

It is often a thujone oil. α-Thujone and β-thujone are monoterpene ketones, and in many plants they lead the oil.

Wormwood also occurs in sabinyl-acetate and cis-epoxyocimene chemotypes, so thujone content varies widely between oils. Distillation turns precursors in the herb into deep-blue chamazulene, which the fresh plant does not contain.

Wormwood is one of the classic bitters of Western herbal medicine. The dried herb is taken before meals for appetite and digestion, and its English name records its old use against intestinal worms.

The oil has been studied in the lab. It inhibits bacteria in culture, most strongly gram-positive species ^{87Reference 87Joshi · 2013In vitroVolatile composition and antimicrobial activity of the essential oil of Artemisia absinthium growing in the Western Ghats region of North West Karnataka, India — in vitroView study →}. In a screen of seven western Canadian Artemisia oils, wormwood’s was the most active against staphylococci ^{89Reference 89Lopes-Lutz et al. · 2008In vitroScreening of chemical composition, antimicrobial and antioxidant activities of Artemisia essential oils — in vitroView study →}.

Formulated in nanocochleates, the oil was active against cutaneous leishmaniasis in the test tube and in an animal model ^{90Reference 90Tamargo et al. · 2017In vitroIn vitro and in vivo evaluation of essential oil from Artemisia absinthium L. formulated in nanocochleates against cutaneous leishmaniasis — animal modelView study →}. Wormwood’s human trials, in Crohn’s disease, used the dried herb rather than the oil ^{91Reference 91Omer et al. · 2007RCTSteroid-sparing effect of wormwood (Artemisia absinthium) in Crohn’s disease: a double-blind placebo-controlled study — randomised placebo-controlled trialView study →92Reference 92Krebs et al. · 2010Clinical trialWormwood (Artemisia absinthium) suppresses tumour necrosis factor alpha and accelerates healing in patients with Crohn’s disease — controlled clinical trialView study →}.

Caution: Thujone blocks the GABA-A receptor and causes convulsions at high doses ^{93Reference 93Höld et al. · 2000Höld, K. M., Sirisoma, N. S., Ikeda, T., Narahashi, T., & Casida, J. E. (2000). α-Thujone (the active component of absinthe): gamma-aminobutyric acid type A receptor modulation and metabolic detoxification. Proceedings of the National Academy of Sciences USA. https://pubmed.ncbi.nlm.nih.gov/10725394/View study →}. It is concentrated in the oil, which is not taken internally. Absinthe’s old reputation was long blamed on thujone, but the levels in the drink were too low to reach a toxic threshold ^{94Reference 94Lachenmeier · 2010ReviewWormwood (Artemisia absinthium L.) — a curious plant with both neurotoxic and neuroprotective properties? — review/commentaryView study →}. Wormwood is traditionally an emmenagogue and abortifacient, so the oil is avoided in pregnancy. People allergic to the daisy family may react to it.

Sweet wormwood is the sweetly aromatic annual from which the antimalarial artemisinin was isolated. Its essential oil is a separate product, a by-product of a crop grown for the drug ^{95Reference 95Bilia et al. · 2014Essential Oil of Artemisia annua L.: An Extraordinary Component with Numerous Antimicrobial PropertiesView study →}.

The herb usually yields 0.3–0.4% oil, and selected strains reach 4% ^{95Reference 95Bilia et al. · 2014Essential Oil of Artemisia annua L.: An Extraordinary Component with Numerous Antimicrobial PropertiesView study →}.

It is usually an artemisia ketone oil, with 1,8-cineole and camphor as its other main compounds. Which of the three leads depends largely on where the plant grew ^{95Reference 95Bilia et al. · 2014Essential Oil of Artemisia annua L.: An Extraordinary Component with Numerous Antimicrobial PropertiesView study →}.

In Chinese medicine the herb is qinghao, a cold, bitter remedy for fevers. That tradition, and the malaria research, belong to the herb and to artemisinin rather than to the distilled oil.

The oil has been tested widely against bacteria and fungi, with activity against both gram-positive and gram-negative species. The studies used different methods, which makes them hard to compare ^{95Reference 95Bilia et al. · 2014Essential Oil of Artemisia annua L.: An Extraordinary Component with Numerous Antimicrobial PropertiesView study →}.

In one study, the oil inhibited multidrug-resistant E. coli more strongly than ethanolic or aqueous extracts of the herb ^{97Reference 97Golbarg et al. · 2021In vitroAntibacterial potency of medicinal plants including Artemisia annua against multidrug-resistant E. coli — in vitroView study →}. A Serbian oil showed relatively low toxicity in animal tests ^{96Reference 96Radulović et al. · 2013Toxic essential oilsView study →}.

Caution: The oil is ketone-rich and often camphor-rich, and it is not taken internally. A. annua pollen is a major cause of hay fever and asthma in northern China ^{98Reference 98Wang et al. · 2025In vitroImmunoproteomic analysis and identification of possible allergenic proteins in Artemisia annua pollen — in vitro / animalView study →}, and people allergic to the daisy family may react. The herb has not been studied in pregnancy, where it is best avoided.

Tarragon oil is distilled from the anise-scented herb of the daisy family, a classic of French cooking. The herb holds 0.15–3.1% oil ^{99Reference 99Obolskiy D et al. · 2011ReviewArtemisia dracunculus L. (tarragon): a critical review of its traditional use, chemical composition, pharmacology, and safety — reviewView study →}.

It is a phenylpropene oil, usually led by estragole. The compound takes its name from estragon, the French word for tarragon.

Methyleugenol, elemicin, and the monoterpene sabinene make up much of the rest. Their proportions vary widely between cultivars and places of origin ^{99Reference 99Obolskiy D et al. · 2011ReviewArtemisia dracunculus L. (tarragon): a critical review of its traditional use, chemical composition, pharmacology, and safety — reviewView study →}.

Tarragon’s traditional uses belong to the herb. European herbalists put a leaf paste with honey on bruises, and Central Asian folk medicine uses tarragon for skin irritation, allergic rashes, and dermatitis. Aromatherapists treat the oil as a middle note.

The oil has a small body of animal and lab work. Injected into rodents, it reduced pain in standard tests ^{100Reference 100Maham M et al. · 2014AnimalAntinociceptive effect of the essential oil of tarragon (Artemisia dracunculus) — animal model (rat/mouse)View study →}. It also had anti-seizure activity in rodents, though some effective doses sedated them ^{101Reference 101Sayyah M et al. · 2004AnimalAnticonvulsant activity and chemical composition of Artemisia dracunculus L. essential oil — animal modelView study →}.

In culture, it inhibited Staphylococcus aureus and Escherichia coli ^{102Reference 102Raeisi M et al. · 2012In vitroEssential oil of tarragon (Artemisia dracunculus) antibacterial activity on Staphylococcus aureus and Escherichia coli — in vitroView study →}.

The best-known tarragon research, on blood sugar, used an alcohol extract of Russian tarragon rather than the oil ^{103Reference 103Ribnicky DM et al. · 2006AnimalAntihyperglycemic activity of Tarralin, an ethanolic extract of Artemisia dracunculus L. — animal model (mouse)View study →}.

Caution: Depending on the cultivar, the oil can hold up to 82% estragole and 39% methyleugenol ^{99Reference 99Obolskiy D et al. · 2011ReviewArtemisia dracunculus L. (tarragon): a critical review of its traditional use, chemical composition, pharmacology, and safety — reviewView study →}. Estragole given to mice induced liver tumours ^{104Reference 104Ekiert H et al. · 2021ReviewArtemisia dracunculus (tarragon): a review of its traditional uses, phytochemistry and pharmacology — reviewView study →}, and tarragon oil damaged DNA in a bacterial test, an effect traced to its estragole ^{105Reference 105Zani F et al. · 1991In vitroStudies on the genotoxic properties of essential oils with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay — in vitroView study →}. The oil is not for sustained internal use. Tarragon’s oils can also cause contact dermatitis ^{106Reference 106North Carolina State Extension (n.d.)Artemisia dracunculus (Tarragon) — species description, cultivars, native range, growing conditions and toxicity — plant databaseView study →}, and as a daisy-family plant it may cross-react in people allergic to ragweed or mugwort. The oil is best avoided in pregnancy and while breastfeeding.

Fringed sagewort is a low, silver-grey wormwood of dry steppes and prairies, from Siberia and Mongolia to the northern Plains of North America. Its oil has a camphor scent.

The oil is led by camphor, 1,8-cineole, and bornyl acetate, which dominate 93–95% of samples across Eurasia. Germacrene D is the main sesquiterpene in about two-thirds of them ^{107Reference 107Zhigzhitzhapova et al. · 2023ReviewEssential oils of Artemisia frigida plants (Asteraceae): conservatism and lability of the composition — phytochemistry reviewView study →}.

The plant’s long folk record is as a tea, drunk in Siberia as sagaan aya and on the Plains for colds and coughs. In Alaska’s Fort Yukon region, the steam from boiled leaves and stems was inhaled for congestion ^{109Reference 109McWilliams · 2003Artemisia frigida, fringed sagebrushView study →}.

In a screen of seven western Canadian Artemisia oils, this one among them, the oils inhibited bacteria, yeasts, and dermatophytes as a group ^{89Reference 89Lopes-Lutz et al. · 2008In vitroScreening of chemical composition, antimicrobial and antioxidant activities of Artemisia essential oils — in vitroView study →}. A Siberian tincture of the herb had about 20 times the radical-scavenging activity of the oil ^{110Reference 110Dylenova et al. · 2023In vitroArtemisia frigida Willd. of the Baikal region (Siberia): essential oils, tincture, and antiradical activity — in vitroView study →}.

Caution: Camphor can make up about 40% of the oil, and some populations carry substantial thujone ^{108Reference 108Korolyuk et al. · 2010Chemical composition of the essential oil from two wormwood species, Artemisia frigida and Artemisia argyrophylla — phytochemistryView study →}. Both are toxic in overdose, so the oil is not taken internally. Avoid it in pregnancy. As a daisy-family plant it may cross-react in people sensitised to ragweed, mugwort, or chamomile.

Estafiate is a silver-leaved North American wormwood, drunk in Mexico as a bitter tea for stomach complaints. Plains peoples burned the dried leaves as a purifying smoke.

Its oil is usually led by camphor and 1,8-cineole, with borneol and α-terpineol behind them ^{111Reference 111Swor et al. · 2024The essential oil compositions of Ambrosia acanthicarpa Hook., Artemisia ludoviciana Nutt., and Gutierrezia sarothrae (Pursh) Britton & Rusby (Asteraceae) from the Owyhee Mountains of Idaho — analyticalView study →}.

The name “white sage” is also used for Salvia apiana, a Californian sage of the mint family, which is a different plant ^{112Reference 112California Native Plant Society (n.d.)White sage, Salvia apiana — species profileView study →}.

Injected into mice, the oil reduced both phases of the formalin pain test and raised hot-plate latency. Naloxone blocked the effect, which suggests it works partly through opioid receptors ^{113Reference 113Anaya-Eugenio et al. · 2016AnimalAntinociceptive activity of the essential oil from Artemisia ludoviciana — animal modelView study →}.

In diabetic mice, the infusion and an organic extract lowered blood glucose, while the oil was inactive ^{114Reference 114Anaya-Eugenio et al. · 2014AnimalHypoglycemic properties of some preparations and compounds from Artemisia ludoviciana Nutt. — animal modelView study →}.

Caution: The oil is usually camphor-rich. Camphor causes seizures in overdose, and poison-centre guidance sends anyone who has swallowed more than 30 mg/kg of a camphor product to hospital ^{115Reference 115Manoguerra et al. · 2006Camphor poisoning: an evidence-based practice guideline for out-of-hospital management — clinical guidelineView study →}. Thujone was absent from most samples tested ^{111Reference 111Swor et al. · 2024The essential oil compositions of Ambrosia acanthicarpa Hook., Artemisia ludoviciana Nutt., and Gutierrezia sarothrae (Pursh) Britton & Rusby (Asteraceae) from the Owyhee Mountains of Idaho — analyticalView study →}. The plant’s sesquiterpene lactones made it a medium-strength skin sensitiser in guinea pigs ^{116Reference 116Zeller et al. · 1985AnimalThe sensitizing capacity of Compositae plantsView study →}. It is avoided in pregnancy.

Big sagebrush is the silver-grey, three-toothed shrub that covers the dry basins of western North America. Its leaves and branches are burned as a smudge in cleansing rituals.

The leaf oil is rich in camphor and 1,8-cineole, with α-pinene and camphene. Fresh herbage yields 0.25–1.69% oil, depending on the variety ^{117Reference 117Zheljazkov et al. · 2022In vitroEssential oil yield, composition, and bioactivity of sagebrush species in the Bighorn Mountains — in vitroView study →}.

Many peoples of the American West used the plant for colds. The Kawaiisu inhaled the fumes of a decoction for head and chest colds, and the Havasupai breathed the smoke of leafy stems laid on the fire ^{118Reference 118Botanical Research Institute of TexasNative American Ethnobotany Database: Artemisia tridentataView study →}.

A 1967 study found the oil inhibited four aerobic bacteria, with Staphylococcus aureus the most sensitive ^{119Reference 119Nagy et al. · 1967In vitroAntibacterial action of essential oils of Artemisia as an ecological factorView study →}. A 2022 study of Bighorn Mountain oils found no significant antimicrobial, antimalarial, or antileishmanial activity ^{117Reference 117Zheljazkov et al. · 2022In vitroEssential oil yield, composition, and bioactivity of sagebrush species in the Bighorn Mountains — in vitroView study →}.

Caution: No formal toxicology exists for big sagebrush. Some oils contain cis-thujone ^{117Reference 117Zheljazkov et al. · 2022In vitroEssential oil yield, composition, and bioactivity of sagebrush species in the Bighorn Mountains — in vitroView study →}, so the oil is not taken internally and is avoided in pregnancy. Big sagebrush is not culinary sage, which is an unrelated mint-family plant.

Mugwort is the tall, aromatic “mother of herbs” of medieval Europe. Its dried, woolly leaves are the moxa burned in moxibustion ^{120Reference 120Ekiert et al. · 2020ReviewSignificance of Artemisia vulgaris L. (Common Mugwort) in the History of Medicine and Its Possible Contemporary Applications — reviewView study →}.

The oil is about 72% monoterpenoids and 26% sesquiterpenoids. 1,8-Cineole, sabinene, camphor, camphene, and the thujones are the compounds found most often ^{120Reference 120Ekiert et al. · 2020ReviewSignificance of Artemisia vulgaris L. (Common Mugwort) in the History of Medicine and Its Possible Contemporary Applications — reviewView study →}.

Mugwort is a traditional dream herb, drunk as a bedtime tea or put into a dream pillow. It is also a bitter for poor appetite and a menstrual herb, uses that belong to the dried herb.

The oil eased chemically induced gut inflammation in zebrafish ^{123Reference 123Meng R et al. · 2022AnimalEssential oil from Artemisia vulgaris alleviates enteritis in zebrafish via oxidative stress and inflammatory modulation — animal modelView study →}. A leaf oil from Manipur, rich in cineole, sabinene, and borneol, inhibited bacteria and fungi in culture ^{122Reference 122Singh NB et al. · 2023In vitroPhytochemical composition and antimicrobial activity of essential oil from Artemisia vulgaris leaves — in vitroView study →}. Another oil, about 29% camphor, killed and repelled a plant-pest mite ^{124Reference 124Kunnathattil M et al. · 2025In vitroChemical composition, acaricidal and repellent activities of Artemisia vulgaris essential oil — in vitroView study →}.

Caution: Large doses of the oil may cause nausea, vomiting, and nervous-system effects. The European Food Safety Authority lists its thujone, camphor, and 1,8-cineole as potentially harmful in food or supplements ^{120Reference 120Ekiert et al. · 2020ReviewSignificance of Artemisia vulgaris L. (Common Mugwort) in the History of Medicine and Its Possible Contemporary Applications — reviewView study →}. Avoid it in pregnancy, since large doses of the herb may cause miscarriage. Mugwort pollen is a major hay-fever allergen, and people allergic to the daisy family may react.

Lemon myrtle is a tree native only to coastal Queensland. Plantations from north Queensland to northern New South Wales grow it for dried leaf and for oil ^{125Reference 125Southwell · 2021Backhousia citriodora FView study →}.

The fresh leaf yields 1–3% oil, and it is the richest natural source of citral known. Steam-distilled lemon myrtle oil is typically 90–98% citral, against 2–3% in lemon peel oil itself ^{125Reference 125Southwell · 2021Backhousia citriodora FView study →}.

It is an aldehyde oil. Citral is a pair of isomers, geranial and neral, that together give the sharp lemon smell.

The oil is used to give a lemon or verbena scent to foods, cosmetics, aromatherapy massage oils, and household products. The leaf is sold as a native-food flavouring ^{125Reference 125Southwell · 2021Backhousia citriodora FView study →}.

In culture, the oil inhibited Staphylococcus aureus, MRSA, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Propionibacterium acnes, much like citral alone ^{126Reference 126Hayes et al. · 2002In vitroToxicity of Australian essential oil Backhousia citriodora (Lemon myrtle)View study →}.

In a small trial in 31 children with molluscum contagiosum, a 10% solution was applied once a day. After 21 days, lesions fell by more than 90% in 9 of 16 children on lemon myrtle, against none of those given olive oil. No adverse events were reported ^{127Reference 127Burke et al. · 2004Essential oil of Australian lemon myrtle (Backhousia citriodora) in the treatment of molluscum contagiosum in childrenView study →}.

Caution: In cell culture, both the oil and citral were highly toxic to human skin cells, while a product holding 1% oil was low in toxicity ^{126Reference 126Hayes et al. · 2002In vitroToxicity of Australian essential oil Backhousia citriodora (Lemon myrtle)View study →}. Neat oil damaged the outer layer of excised human skin, and a 1% product caused limited damage ^{128Reference 128Hayes et al. · 2003Toxicity of Australian essential oil Backhousia citriodora (lemon myrtle)View study →}. Citral irritates and sensitises skin at high concentrations, so use the oil well diluted. Because citral has shown reproductive toxicity in animals, citral-rich oils are best restricted in pregnancy ^{125Reference 125Southwell · 2021Backhousia citriodora FView study →}.

Birch oil comes from the bark of the sweet birches, such as Betula lenta and B. alleghaniensis. Their bark is rich in methyl salicylate, which gives it a sharp wintergreen smell. The bark yields only 0.07–0.1% oil ^{129Reference 129Dosoky et al. · 2022Authentication and market survey of sweet birch (Betula lenta L.) essential oil}.

That makes birch a close chemical relative of wintergreen oil, which is mostly methyl salicylate. The compound is an ester of salicylic acid.

Methyl salicylate belongs to the same salicylate family as aspirin, but it is a different molecule. Salicylic acid, the parent of aspirin, was first isolated in 1838 by oxidising salicin, the glucoside of willow and meadowsweet ^{131Reference 131Marson P · 2006Marson P, Pasero G (2006). [The Italian contributions to the history of salicylates]. Reumatismo. https://pubmed.ncbi.nlm.nih.gov/16639491/View study →}.

Aspirin itself is acetylsalicylic acid. Felix Hoffmann at Bayer made it in 1897 by acetylating salicylic acid, which was too harsh on the stomach ^{132Reference 132Ozleyen A et al. · 2023Looking at NSAIDs from a historical perspective and their current status in drug repurposing for cancer treatment and preventionView study →}.

Like wintergreen, birch is traditionally used as a warming rub. It goes into liniments for sore muscles and joints.

Much of what is sold as birch oil is something else. None of 27 commercial “birch” oils tested carried the birch marker compounds, and several showed signs of wintergreen oil, synthetic methyl salicylate, or castor oil ^{129Reference 129Dosoky et al. · 2022Authentication and market survey of sweet birch (Betula lenta L.) essential oil}.

Caution: Methyl salicylate is toxic in small amounts if swallowed, and it is readily absorbed through the skin. Wintergreen is among the essential oils that are toxic in small amounts ^{3Reference 3Poison Control (National Capital Poison Essential Oils: Poisonous When Misused}. Use birch well diluted, keep it away from children, and avoid it with a salicylate allergy or alongside blood thinners or aspirin.

Somali frankincense comes from northern Somalia and Somaliland, where harvesters call the resin beeyo ^{135Reference 135Johnson et al. · 2019Organic Certification is Not Enough: The Case of the Methoxydecane FrankincenseView study →}. Many botanists treat B. carterii as part of B. sacra. Its oil has a different optical rotation and a different balance of α-pinene enantiomers, which some chemists take as a sign of a separate species ^{138Reference 138Woolley et al. · 2012Chemical differentiation of Boswellia sacra and Boswellia carterii essential oils by gas chromatography and chiral gas chromatography-mass spectrometryView study →}.

The resin typically yields 4–8% oil ^{135Reference 135Johnson et al. · 2019Organic Certification is Not Enough: The Case of the Methoxydecane FrankincenseView study →}. It is a monoterpene oil, usually led by α-pinene, limonene, or both.

Aromatherapists use frankincense in meditative blends and in blends meant to rejuvenate the skin. The oil is also inhaled for the chest.

Much frankincense oil on the market is mixed. In 9 of 13 commercial frankincense oils, including 4 of 5 certified organic ones, analysts found methoxydecane. It is the marker of a different tree, B. occulta, whose resin is gathered alongside B. carterii ^{135Reference 135Johnson et al. · 2019Organic Certification is Not Enough: The Case of the Methoxydecane FrankincenseView study →}.

Of 21 commercial frankincense oils in another survey, six held synthetic limonene, three synthetic octyl acetate, and three castor oil ^{137Reference 137Ojha et al. · 2022Comparison of Volatile Constituents Present in Commercial and Lab-Distilled Frankincense (Boswellia carteri) Essential Oils for AuthenticationView study →}.

Caution: The oil is mostly monoterpenes, which oxidise with age, so keep it fresh, diluted, and patch-tested.

Boswellia frereana is a Somali frankincense whose resin harvesters call maydi, distinct from the beeyo of B. carterii ^{135Reference 135Johnson et al. · 2019Organic Certification is Not Enough: The Case of the Methoxydecane FrankincenseView study →}.

Its oil is an α-thujene oil, often with a good deal of α-pinene. In twelve single-tree samples, α-thujene made up 14.5–43.9% and α-pinene anywhere from 3.0% to 63.0% ^{139Reference 139Johnson et al. · 2021The Chemical Composition of Single-Tree Boswellia frereana Resin SamplesView study →}. Sabinene and p-cymene are present in moderate amounts ^{140Reference 140DeCarlo et al. · 2023Evaluating the Potential of Boswellia rivae to Provide Sustainable Livelihood Benefits in Eastern EthiopiaView study →}.

Its resin lacks the incensole-type diterpenes found in the other main species, and holds instead many dimers of α-phellandrene ^{136Reference 136Hamm et al. · 2005A chemical investigation by headspace SPME and GC-MS of volatile and semi-volatile terpenes in various olibanum samplesView study →}.

Caution: As with other frankincense oils, the monoterpenes oxidise with age, so keep the oil fresh, diluted, and patch-tested.

Omani frankincense is the luban of the Arabian incense trade. The resin is also burned as incense in meditation and religious ritual, and its aroma resembles smoky wood.

The oil is a monoterpene oil. It is led by α-pinene, with limonene and α-thujene behind it.

Omani resin is rich in boswellic acids. In one analysis, they made up about 29% of B. sacra resin, against about 16% of Indian frankincense ^{141Reference 141Mannino G et al. · 2016Quantitative Determination of 3-O-Acetyl-11-Keto-βBoswellic Acid (AKBA) and Other Boswellic Acids in Boswellia sacra Flueck (synView study →}. None of them distils into the oil.

The oil itself has been studied mainly in the lab. Oils distilled from four commercial grades of Omani resin all showed marked antibacterial activity, with α-pinene the main component of each ^{142Reference 142Al-Saidi S et al. · 2012In vitroComposition and antibacterial activity of the essential oils of four commercial grades of Omani luban, the oleo-gum resin of Boswellia sacra FLUECK — [in vitro]View study →}.

Frankincense compounds, chiefly AKBA, have been tested against cancer cells in lab and animal studies ^{143Reference 143Efferth T et al. · 2022Systematic reviewAnti-inflammatory and anti-cancer activities of frankincense: Targets, treatments and toxicities — [systematic review]View study →}. There is no clinical evidence that frankincense essential oil treats cancer in people, and it is no substitute for cancer treatment ^{144Reference 144Cancer Council AustraliaDoes Frankincense Oil Have Cancer-Fighting Properties? Link}.

Caution: The oil is mostly monoterpenes, which oxidise with age, so keep it fresh, diluted, and patch-tested. The resin is traditionally an emmenagogue and is avoided by mouth in pregnancy.

Indian frankincense is the salai guggul of Ayurveda, tapped from a deciduous tree of the dry hill forests of India and Pakistan. The resin is best known for its boswellic acids, which go into standardised extracts.

Its oil is usually an α-thujene oil, with smaller amounts of myrcene, sabinene, and α-pinene ^{140Reference 140DeCarlo et al. · 2023Evaluating the Potential of Boswellia rivae to Provide Sustainable Livelihood Benefits in Eastern EthiopiaView study →}. Its resin volatiles also carry estragole (methylchavicol) and methyleugenol, which set it apart from the Somali and Omani species ^{136Reference 136Hamm et al. · 2005A chemical investigation by headspace SPME and GC-MS of volatile and semi-volatile terpenes in various olibanum samplesView study →}.

Those two compounds can be substantial. In oil distilled from five batches of an Indian frankincense extract, estragole made up 9.9–21.6% and methyleugenol 2.9–7.7% ^{145Reference 145EFSA Panel on Additives et al. · 2022Safety and efficacy of a feed additive consisting of an extract of olibanum from Boswellia serrata Roxb. ex Colebr. for use in dogs and horses (FEFANA asbl)View study →}.

Resin sold as Indian frankincense also varies. Across ten batches, the resin held 2.5–9.1 mg of octyl acetate per gram, against 0.02–0.15 mg of α-pinene ^{146Reference 146Song Z et al. · 2012Song Z, Xia L, Wei Z, Cao Y, Zhang L, & Liu Z (2012). [Determination of alpha-pinene and octyl acetate contents in Boswellia serrata] — [analytical chemistry study]. Zhongguo Zhong Yao Za Zhi, 37(10), 1431-3. https://pubmed.ncbi.nlm.nih.gov/22860456/View study →}.

Most of frankincense’s human research tested standardised B. serrata extracts, high in AKBA and taken by mouth. Pooled trials in knee osteoarthritis favoured them for pain and function scores ^{147Reference 147Yu G et al. · 2020Meta-analysisEffectiveness of Boswellia and Boswellia extract for osteoarthritis patients: a systematic review and meta-analysis — [systematic review and meta-analysis]View study →}. Those results belong to the extracts, and they do not carry over to the essential oil.

Caution: Estragole and methyleugenol are the same compounds that limit tarragon and basil oils, so this oil is not for internal use. In the lab, frankincense resin extracts inhibited the main drug-metabolising liver enzymes ^{148Reference 148Frank A et al. · 2006In vitroAnalysis of frankincense from various Boswellia species with inhibitory activity on human drug metabolising cytochrome P450 enzymes using liquid chromatography mass spectrometry after automated on-line extraction — [in vitro enzyme study]View study →}. Isolated AKBA was toxic to developing zebrafish embryos ^{149Reference 149Han L et al. · 2022In vitroInduction of developmental toxicity and cardiotoxicity in zebrafish embryos/larvae by acetyl-11-keto-β-boswellic acid (AKBA) through oxidative stress — [in vitro / zebrafish developmental toxicity]View study →}, and the resin is avoided in pregnancy.

Ylang-ylang oil is distilled from the drooping yellow flowers of a tropical tree in the custard-apple family. The flowers become strongly fragrant only once they turn yellow, and their scent peaks at night.

The Comoros, Madagascar, and Mayotte are the main producers. The oil is a major raw material of the perfume industry.

Fresh flowers give about 0.5–0.8% oil by distillation ^{150Reference 150Chakira et al. · 2025Improving the quality of ylang-ylang essential oils [Cananga odorata (Lam.) Hook.f. & Thomson] through microwave-assisted extraction compared to conventional extraction methods}.

Chemically it is a benzenoid ester and sesquiterpene oil. Its fragrant fraction is led by linalool, benzyl acetate, p-cresyl methyl ether, and methyl benzoate. Its heavier fraction is mostly germacrene D and β-caryophyllene.

The oil is sold in fractions, collected one after another during a single distillation: Extra, First, Second, and Third. The ISO standard adds an Extra Superior grade for oil from the Comoros, and a “Complete” grade is sold too.

Extra is richest in the light esters, the ether, and linalool, and goes into fine perfume. First and Second go into cosmetics, and Third into soap.

Aromatherapists use ylang-ylang as a euphoric, calming, and aphrodisiac oil, and for nervous tension and high blood pressure. In Indonesia it is used to heighten pleasure and ease anxiety during sex, and Polynesians scent coconut oil with the flowers for massage.

It is a powerful blend modifier and easy to overdo.

Blood pressure is the most consistent finding. Inhaled by 24 healthy volunteers, the oil lowered blood pressure and pulse while raising alertness, which the authors called “harmonisation” rather than sedation ^{151Reference 151Hongratanaworakit et al. · 2004RCTEvaluation of the harmonizing effect of ylang-ylang oil on humans after inhalation — randomized controlled trialView study →}. Applied to the skin in 40 volunteers, it lowered blood pressure and left people feeling calmer ^{152Reference 152Hongratanaworakit et al. · 2006Clinical trialRelaxing effect of ylang ylang oil on humans after transdermal absorption — clinical trialView study →}.

In people with high blood pressure it has been tested only in blends, such as lavender and ylang-ylang pads worn for 14 days ^{153Reference 153Napavichayanun et al. · 2024RCTEffect of Lavandula angustifolia and Cananga odorata sticker pads on blood pressure in high blood pressure volunteers — randomized controlled trialView study →}.

The calming results are mixed. A pilot trial in nursing staff found no effect on anxiety ^{154Reference 154Gnatta et al. · 2014RCTAromatherapy with ylang ylang for anxiety and self-esteem: a pilot randomized controlled trialView study →}, and in 144 volunteers the aroma raised calmness but slowed memory and processing speed ^{155Reference 155Moss et al. · 2008RCTModulation of cognitive performance and mood by aromas of peppermint and ylang-ylang — randomized controlled trialView study →}.

In mice, the inhaled oil was anxiolytic, and benzyl benzoate, linalool, and benzyl alcohol were each anxiolytic as isolated compounds ^{156Reference 156Zhang et al. · 2016AnimalThe anxiolytic effect of essential oil of Cananga odorata exposure on mice and determination of its major active constituents — animal modelView study →}.

Caution: Ylang-ylang is a known skin sensitiser. In clinic patch-test data, 3.9% of dermatitis patients reacted to it, with masseurs and cosmeticians at higher risk ^{157Reference 157Geier et al. · 2022ObservationalContact sensitization to essential oils: IVDK data 2010–2019 — observationalView study →}.

Dilute it, patch-test first, and keep it off damaged skin. It is not taken by mouth, it may add to blood-pressure medicines, and it has not been studied in pregnancy.

Elemi is a soft, resinous oil with a lemony edge. The crude resin is rich in it, giving about a quarter of its weight as oil ^{158Reference 158Coppen · 1995Gums, Resins and Latexes of Plant Origin}.

Chemically it is a monoterpene oil led by limonene. Behind it sit the sesquiterpene alcohol elemol, α-phellandrene, and the phenylpropene elemicin ^{159Reference 159Kačániová et al. · 2020Chemical composition and antimicrobial activity of selected essential oils against Staphylococcus spp. isolated from human semenView study →160Reference 160Nikolic et al. · 2016Sensitivity of clinical isolates of Candida to essential oils from Burseraceae familyView study →}.

Elemi resin is one of the listed natural sources of elemicin. This phenylpropene is better known from nutmeg.

Aromatherapists use elemi in meditation blends. It also goes into blends meant to rejuvenate the skin.

The research is all in the lab. Elemi was among the four most active of 14 commercial oils against Staphylococcus bacteria isolated from human semen ^{159Reference 159Kačániová et al. · 2020Chemical composition and antimicrobial activity of selected essential oils against Staphylococcus spp. isolated from human semenView study →}.

Another commercial elemi oil inhibited Candida yeasts taken from the mouth, though a frankincense oil tested beside it was stronger ^{160Reference 160Nikolic et al. · 2016Sensitivity of clinical isolates of Candida to essential oils from Burseraceae familyView study →}.

Caution: Treat it like any resin oil. Dilute it in a carrier oil and patch-test a small area of skin first. Keep the bottle closed and use the oil fresh, since oxidised limonene is a recognised contact allergen ^{79Reference 79Sukakul T et al. · 2022ObservationalContact allergy to oxidized linalool and oxidized limonene: patch testing in consecutive patients — observationalView study →}.

Caraway oil is distilled from the ripe fruits of a biennial herb of the carrot family. The fruit holds 3–7% oil ^{161Reference 161European Medicines Agency · 2015Assessment report on Carum carvi L., fructus and Carum carvi L., aetheroleum (EMA/HMPC/715093/2013) — regulatory assessment report: constituents, historical use and posology. https://www.ema.europa.eu/en/documents/herbal-report/final-assessment-report-carum-carvi-l-fructus-and-carum-carvi-l-aetheroleum_en.pdfView study →}.

It is a ketone oil, built on (+)-carvone and limonene ^{161Reference 161European Medicines Agency · 2015Assessment report on Carum carvi L., fructus and Carum carvi L., aetheroleum (EMA/HMPC/715093/2013) — regulatory assessment report: constituents, historical use and posology. https://www.ema.europa.eu/en/documents/herbal-report/final-assessment-report-carum-carvi-l-fructus-and-carum-carvi-l-aetheroleum_en.pdfView study →}.

Caraway’s carvone is the same mirror-image form as dill’s. The opposite form is the carvone of spearmint oil ^{161Reference 161European Medicines Agency · 2015Assessment report on Carum carvi L., fructus and Carum carvi L., aetheroleum (EMA/HMPC/715093/2013) — regulatory assessment report: constituents, historical use and posology. https://www.ema.europa.eu/en/documents/herbal-report/final-assessment-report-carum-carvi-l-fructus-and-carum-carvi-l-aetheroleum_en.pdfView study →}.

Caraway oil is a traditional carminative, used for wind, bloating, and mild digestive cramps. The European Union registers the oil for bloating and flatulence on the basis of traditional use ^{162Reference 162European Medicines Agency · 2015ReviewEuropean Union herbal monograph on Carum carvi L., aetheroleum (EMA/HMPC/715094/2013) — [regulatory monograph]. https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-carum-carvi-l-aetheroleum_en.pdfView study →}.

The clinical research tests caraway oil only in a fixed, enteric-coated capsule with peppermint oil. In 96 people with functional dyspepsia, the capsule cut pain by 40%, against 22% on placebo ^{163Reference 163May B et al. · 2000RCTEfficacy and tolerability of a fixed combination of peppermint oil and caraway oil in patients suffering from functional dyspepsia — [human RCT, double-blind, placebo-controlled, n=96]View study →}. In a second trial it matched the drug cisapride ^{164Reference 164Madisch A et al. · 1999RCTTreatment of functional dyspepsia with a fixed peppermint oil and caraway oil combination preparation as compared to cisapride: a multicenter, reference-controlled double-blind equivalence study — [human RCT, active comparator, n=120]View study →}.

Delivered straight into the duodenum of healthy volunteers, caraway oil relaxed the muscle of the stomach and duodenum ^{165Reference 165Micklefield G et al. · 2003Effects of intraduodenal application of peppermint oil (WS 1340) and caraway oil (WS 1520) on gastroduodenal motility in healthy volunteers — [human crossover, manometry]View study →}. It also stopped the gallbladder from emptying ^{166Reference 166Goerg KJ · 2003RCTEffect of peppermint oil and caraway oil on gastrointestinal motility in healthy volunteers: a pharmacodynamic study using simultaneous determination of gastric and gall-bladder emptying and orocaecal transit time — [human RCT, double-blind crossover, n=12]View study →}.

In the lab the oil is antibacterial, and most of that work concerns preserving food ^{167Reference 167Shad et al. · 2026In vitroApplication of Finnish caraway (Carum carvi) essential oil in gelled lipid-based nanoparticles to enhance the shelf-life of freshwater fish — [in vitro and food study]View study →}.

Caution: Avoid caraway oil with an allergy to the carrot family, such as fennel, anise, celery, coriander, or dill ^{162Reference 162European Medicines Agency · 2015ReviewEuropean Union herbal monograph on Carum carvi L., aetheroleum (EMA/HMPC/715094/2013) — [regulatory monograph]. https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-carum-carvi-l-aetheroleum_en.pdfView study →}. The EU monographs do not recommend medicinal use with liver disease, gallstones, or inflammation of the bile ducts ^{168Reference 168European Medicines Agency · 2015ReviewEuropean Union herbal monograph on Carum carvi L., fructus — [regulatory monograph]View study →162Reference 162European Medicines Agency · 2015ReviewEuropean Union herbal monograph on Carum carvi L., aetheroleum (EMA/HMPC/715094/2013) — [regulatory monograph]. https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-carum-carvi-l-aetheroleum_en.pdfView study →}.

Two people on levothyroxine had a rise in TSH after taking caraway ^{169Reference 169European Medicines Agency · 2020ReviewAddendum to assessment report on Carum carvi L., fructus and aetheroleum (EMA/HMPC/351955/2020) — periodic review; no revision of the monographs. https://www.ema.europa.eu/en/documents/herbal-report/addendum-assessment-report-carum-carvi-l-fructus-and-aetheroleum_en.pdfView study →}. Safety in pregnancy and breastfeeding has not been established ^{162Reference 162European Medicines Agency · 2015ReviewEuropean Union herbal monograph on Carum carvi L., aetheroleum (EMA/HMPC/715094/2013) — [regulatory monograph]. https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-carum-carvi-l-aetheroleum_en.pdfView study →}.

Atlas cedarwood oil comes from the wood of the Atlas cedar, native to the Rif and Atlas mountains of Morocco and Algeria ^{170Reference 170Setzer et al. · 2026ReviewCedarwood oils: the wood essential-oil compositions from trees known as “cedar” — reviewView study →}.

It is a sesquiterpene oil. β-Himachalene alone makes up about two-fifths of a typical commercial oil, with α- and γ-himachalene and the atlantones behind it ^{170Reference 170Setzer et al. · 2026ReviewCedarwood oils: the wood essential-oil compositions from trees known as “cedar” — reviewView study →}.

In the lab, a Moroccan oil was antibacterial and antifungal, most strongly against Gram-positive bacteria ^{173Reference 173El Hachlafi et al. · 2023In vitroAntioxidant, volatile compounds; antimicrobial, anti-inflammatory, and dermatoprotective properties of Cedrus atlantica (Endl.) Manetti ex Carriere essential oil: in vitro and in silico investigationsView study →}. Rodent studies report anti-inflammatory and pain-relieving effects ^{170Reference 170Setzer et al. · 2026ReviewCedarwood oils: the wood essential-oil compositions from trees known as “cedar” — reviewView study →}.

Caution: Dilute it in a carrier oil and patch-test a small area of skin first. It is not taken by mouth.

Himalayan cedarwood oil comes from the deodar, the cedar of the western Himalayas, from Afghanistan to Nepal ^{170Reference 170Setzer et al. · 2026ReviewCedarwood oils: the wood essential-oil compositions from trees known as “cedar” — reviewView study →}.

Its wood oil is close to Atlas cedarwood, led by β-himachalene, but it carries more of the atlantones ^{170Reference 170Setzer et al. · 2026ReviewCedarwood oils: the wood essential-oil compositions from trees known as “cedar” — reviewView study →}.

The needles give a different oil. It is led by α-terpineol at about 30% and linalool at about 24% ^{175Reference 175Zeng WC et al. · 2012In vitroChemical composition, antioxidant, and antimicrobial activities of essential oil from pine needle (Cedrus deodara) — analytical / in vitroView study →}.

In animal studies the wood oil has shown pain-relieving and anti-inflammatory effects, and an antispasmodic effect credited to himachalol. It is also insecticidal ^{170Reference 170Setzer et al. · 2026ReviewCedarwood oils: the wood essential-oil compositions from trees known as “cedar” — reviewView study →}.

Caution: Dilute it in a carrier oil and patch-test a small area of skin first. It is not taken by mouth.

Roman chamomile oil is distilled from the flowering herb of a perennial daisy, also known as Anthemis nobilis. The flowering herb gives about 0.2–1.6% oil ^{176Reference 176Baranauskienė et al. · 2022Valorisation of Roman chamomile (Chamaemelum nobile L.) herb by comprehensive evaluation of hydrodistilled aroma and residual non-volatile fractions177Reference 177Filipović et al. · 2024The first study on cultivating Roman chamomile (Chamaemelum nobile (L.) All.) for its flower and essential oil in southeast Serbia}.

It is an ester oil. Most of it is a long series of angelates, esters of angelic acid ^{178Reference 178Radulović et al. · 2026Unlocking the secrets of Roman chamomile (Anthemis nobilis L.) essential oil: structural elucidation and acute toxicity of new estersView study →}. They give it a soft, sweet, apple-like scent.

It carries far less chamazulene than German chamomile, so it is pale rather than blue.

Aromatherapists use it as a calming, antispasmodic middle note for restlessness and irritability.

Research on the oil itself is early. In zebrafish, the oil at its highest dose reduced anxiety-like behaviour without slowing the fish down ^{179Reference 179Silveira et al. · 2022Anxiolytic effect of Anthemis nobilis L. (roman chamomile) and Citrus reticulata Blanco (tangerine) essential oils using the light-dark test in zebrafish (Danio rerio)View study →}.

Caution: Roman chamomile belongs to the daisy family. Its extract is one of the plant extracts dermatologists patch-test for daisy-family allergy, and contact dermatitis from it is well documented ^{180Reference 180Ključevšek et al. · 2025Allergic potential of medicinal plants from the Asteraceae familyView study →}.