Calendula

Calendula is a vulnerary, or wound herb, first. It is applied to minor wounds, especially slow-healing ones, and to minor burns, sunburn, abrasions, sores and rashes ^{35Reference 35Committee on Herbal Medicinal Products ( · 2018ReviewAssessment report on Calendula officinalis L., flos (EMA/HMPC/603409/2017) — regulatory reviewView study →}. The flowers are used in more forms than most Western herbs: an infused oil, an ointment or cream, a tincture, a compress and a simple infusion ^{35Reference 35Committee on Herbal Medicinal Products ( · 2018ReviewAssessment report on Calendula officinalis L., flos (EMA/HMPC/603409/2017) — regulatory reviewView study →}.

Diluted, the same preparations serve as a gargle or mouth rinse for inflamed gums, mouth ulcers and a sore throat, and as a wash for conjunctivitis and other eye irritation ^{35Reference 35Committee on Herbal Medicinal Products ( · 2018ReviewAssessment report on Calendula officinalis L., flos (EMA/HMPC/603409/2017) — regulatory reviewView study →}. Calendula is also applied to swollen or inflamed lymph glands, sprains and bruises ^{35Reference 35Committee on Herbal Medicinal Products ( · 2018ReviewAssessment report on Calendula officinalis L., flos (EMA/HMPC/603409/2017) — regulatory reviewView study →}.

Taken internally as a tea or tincture, calendula is given for inflammatory conditions of the digestive tract, including gastritis, gastric and duodenal ulcers and colitis ^{35Reference 35Committee on Herbal Medicinal Products ( · 2018ReviewAssessment report on Calendula officinalis L., flos (EMA/HMPC/603409/2017) — regulatory reviewView study →}. It is also used as an emmenagogue, for absent or painful menstruation ^{35Reference 35Committee on Herbal Medicinal Products ( · 2018ReviewAssessment report on Calendula officinalis L., flos (EMA/HMPC/603409/2017) — regulatory reviewView study →}.

The florets are a kitchen and dye plant as well. They are eaten in salads, and the flowers make a yellow dye ^{39Reference 39North Carolina State ExtensionCalendula officinalis (pot marigold) — plant profile, uses and cultivation — horticultural databaseView study →}.

Bioassay-guided fractionation of the flower CO₂ extract identifies the triterpenoids as the main anti-inflammatory principles, and above all the faradiol monoesters because of their quantity. Free faradiol, which is not present in the extract, is the most active compound tested and equals indomethacin in the croton-oil mouse-ear oedema test. The activity of different extracts tracks their monoester content, so it serves as a quality-control marker ^{9,10Reference 9Della Loggia R et al. · 1994In vitroThe role of triterpenoids in the topical anti-inflammatory activity of Calendula officinalis flowers — [in vitro / animal model]View study →Reference 10Zitterl-Eglseer K et al. · 1997In vitroAnti-oedematous activities of the main triterpendiol esters of marigold (Calendula officinalis L.) — [in vitro / mouse model]View study →}.

Chemical modification of these triterpenes produced derivatives with greater potency in the same model ^{11Reference 11Neukirch H et al. · 2005AnimalImproved anti-inflammatory activity of three new terpenoids derived, by systematic chemical modifications, from the abundant triterpenes of the flowery plant Calendula officinalis — [mouse model]View study →}.

A 2025 study confirmed C16-hydroxylated triterpenoids as key contributors, acting in part by modulating interleukin-6 release, and mapped their complete biosynthetic pathway ^{12Reference 12Golubova D et al. · 2025In vitroBiosynthesis and bioactivity of anti-inflammatory triterpenoids in Calendula officinalis — [in vitro mechanistic study]View study →}.

Human evidence is indirect: in a controlled irritant-contact-dermatitis model in healthy volunteers, marigold creams significantly reduced sodium lauryl sulfate–induced skin irritation when applied during the induction phase ^{30Reference 30Fuchs SM et al. · 2005Clinical trialProtective effects of different marigold (Calendula officinalis L.) and rosemary cream preparations against sodium-lauryl-sulfate-induced irritant contact dermatitis — [clinical trial]View study →}.

Gap: the strongest data are animal oedema assays and an experimental irritation model. There is no placebo-controlled trial of calendula for an inflammatory skin disease such as eczema or psoriasis at a defined triterpenoid dose.

The evidence is strongest in the early phases of healing. Animal excision and incision studies and one systematic review report faster resolution of the inflammatory phase and more granulation tissue, and calendula tincture drives fibroblast proliferation and migration through a PI3K/Akt pathway ^{7,13Reference 7Givol O et al. · 2019Systematic reviewA systematic review of Calendula officinalis extract for wound healing — [systematic review]View study →Reference 13Dinda M et al. · 2015In vitroPI3K-mediated proliferation of fibroblasts by Calendula officinalis tincture: implication in wound healing — [in vitro study]View study →}.

In humans the picture is mixed. Two controlled studies on venous leg ulcers found reduced ulcer area, and prospective diabetic-foot-ulcer work reported high closure and pain relief, but a randomised diabetic-leg-ulcer trial found no benefit and a burns trial no advantage over control ^{7,17,18,19Reference 7Givol O et al. · 2019Systematic reviewA systematic review of Calendula officinalis extract for wound healing — [systematic review]View study →Reference 17Kundaković T et al. · 2012RCTTreatment of venous ulcers with the herbal-based ointment Herbadermal®: a prospective non-randomized pilot study — [non-randomised clinical trial]View study →Reference 18Buzzi M et al. · 2016Clinical trialA Prospective, Descriptive Study to Assess the Clinical Benefits of Using Calendula officinalis Hydroglycolic Extract for the Topical Treatment of Diabetic Foot Ulcers — [prospective clinical study]View study →Reference 19Carvalho AF et al. · 2016RCTLow-level laser therapy and Calendula officinalis in repairing diabetic foot ulcers — [randomised controlled trial]View study →}.

Post-surgical trials are more consistently positive: calendula ointment reduced pain and improved redness and oedema after episiotomy, and sped caesarean-wound healing on the REEDA scale ^{14,15,16Reference 14De Angelis C et al. · 2022RCTUse of calendula ointment after episiotomy: a randomized clinical trial — [randomised controlled trial]View study →Reference 15Jahdi F et al. · 2018RCTThe impact of calendula ointment on cesarean wound healing: A randomized controlled clinical trial — [randomised controlled trial]View study →Reference 16Eghdampour F et al. · 2013RCTThe Impact of Aloe vera and Calendula on Perineal Healing after Episiotomy in Primiparous Women: A Randomized Clinical Trial — [randomised controlled trial]View study →}. Two systematic reviews judged the underlying trial quality low and the evidence weak ^{7,8Reference 7Givol O et al. · 2019Systematic reviewA systematic review of Calendula officinalis extract for wound healing — [systematic review]View study →Reference 8Leach MJ et al. · 2008Systematic reviewCalendula officinalis and Wound Healing: A Systematic Review — [systematic review]View study →}.

Gap: almost no trial is placebo-controlled or blinded, “calendula” spans many extract types and formulations, and the one randomised chronic-wound trial (diabetic leg ulcers) was negative.

Two paediatric randomised trials support calendula here. In 66 infants, calendula ointment three times daily for 10 days improved diaper dermatitis significantly and left fewer rash sites than aloe vera cream, with no adverse effects in either arm ^{20Reference 20Panahi Y et al. · 2012RCTA randomized comparative trial on the therapeutic efficacy of topical aloe vera and Calendula officinalis on diaper dermatitis in children — [randomised controlled trial]View study →}. A triple-blind trial in 73 children found 1.5% calendula and 1.5% olive ointments produced statistically indistinguishable healing over 7 days ^{21Reference 21Sharifi-Heris Z et al. · 2018RCTComparison the effects of topical application of olive and calendula ointments on Children’s diaper dermatitis: A triple-blind randomized clinical trial — [randomised controlled trial]View study →}. Both are small and single-centre.

Neither trial included a placebo or a zinc-oxide barrier-cream arm, so they show parity with a botanical comparator rather than an effect size for calendula itself.

In a six-month randomised trial in 240 gingivitis patients, a diluted calendula tincture mouthrinse (2 mL in 6 mL water, twice daily) significantly reduced plaque, gingival and bleeding indices compared with a placebo rinse ^{22Reference 22Khairnar MS et al. · 2013RCTEvaluation of Calendula officinalis as an anti-plaque and anti-gingivitis agent — [randomised controlled trial]View study →}.

A 2024 double-blind trial of a multi-botanical gel containing calendula, propolis, aloe, green tea and cranberry matched conventional toothpaste on gingival inflammation, while shifting the crevicular-fluid proteome toward a host-immune profile ^{23Reference 23Figueiredo LC et al. · 2024RCTThe Effect of a Nature-Based Gel on Gingival Inflammation and the Proteomic Profile of Crevicular Fluid: A Randomized Clinical Trial — [randomised controlled trial]View study →}.

The first trial tested a home-diluted tincture rather than a standardised product, and the second cannot separate calendula from four other actives.

In an 80-woman double-blind randomised trial, a calendula extract cream matched metronidazole for bacterial vaginosis, clearing symptoms in both arms with no side effects ^{24Reference 24Pazhohideh Z et al. · 2018RCTThe effect of Calendula officinalis versus metronidazole on bacterial vaginosis in women: A double-blind randomized controlled trial — [randomised controlled trial]View study →}. In 150 women, a calendula vaginal cream matched clotrimazole for vaginal candidiasis, acting more slowly but achieving a higher long-term negative-culture rate ^{25Reference 25Saffari E et al. · 2017RCTComparing the effects of Calendula officinalis and clotrimazole on vaginal Candidiasis: A randomized controlled trial — [randomised controlled trial]View study →}.

In vitro the results are inconsistent. Calendula glycolic extract inhibited multidrug-resistant Klebsiella and Pseudomonas biofilms only modestly (MIC 1.56–50 mg/mL, weaker than a chilli-pepper comparator) ^{26Reference 26do Rosário Palma AL et al. · 2023In vitroEffects of Calendula officinalis and Capsicum annum glycolic extracts on planktonic cells and biofilms of multidrug-resistant strains of Klebsiella pneumoniae and Pseudomonas aeruginosa — [in vitro study]View study →}, and several formulation studies found it among the weaker botanicals tested against skin flora.

The positive evidence is confined to the two gynaecological trials. Direct antibacterial potency in vitro is low and depends heavily on the extract.

The landmark phase III trial (Pommier 2004, 254 breast-cancer patients) found calendula ointment cut grade 2 or higher acute dermatitis from 63% to 41% compared with trolamine, with less pain and fewer treatment interruptions ^{1Reference 1Pommier P et al. · 2004RCTPhase III randomized trial of Calendula officinalis compared with trolamine for the prevention of acute dermatitis during irradiation for breast cancer — [randomised controlled trial]View study →}. A smaller head-and-neck trial (51 patients) favoured calendula over essential fatty acids ^{4Reference 4Schneider F et al. · 2015RCTUsage of Calendula officinalis in the prevention and treatment of radiodermatitis: a randomized double-blind controlled clinical trial — [randomised controlled trial]View study →}.

The two largest replications were null. A 420-patient blinded trial found no difference from aqueous (Essex) cream ^{2Reference 2Sharp L et al. · 2013RCTNo differences between Calendula cream and aqueous cream in the prevention of acute radiation skin reactions—results from a randomised blinded trial — [randomised controlled trial]View study →}, and an 82-patient trial found none compared with sorbolene ^{3Reference 3Siddiquee S et al. · 2021RCTEfficacy of topical Calendula officinalis on prevalence of radiation-induced dermatitis: A randomised controlled trial — [randomised controlled trial]View study →}. Two meta-analyses then pooled the data and found no significant reduction in radiation-dermatitis incidence ^{5,6Reference 5Robijns J et al. · 2023Meta-analysisNatural and miscellaneous agents for the prevention of acute radiation dermatitis: a systematic review and meta-analysis — [systematic review and meta-analysis]View study →Reference 6Ginex PK et al. · 2020Meta-analysisRadiodermatitis in Patients With Cancer: Systematic Review and Meta-Analysis — [systematic review and meta-analysis]View study →}.

Gap: blinded replications against modern emollients found no difference, the pooled data show no benefit, and one meta-analysis reported that calendula increased radiodermatitis risk ^{6Reference 6Ginex PK et al. · 2020Meta-analysisRadiodermatitis in Patients With Cancer: Systematic Review and Meta-Analysis — [systematic review and meta-analysis]View study →}.

Calendula flower extracts scavenge free radicals (DPPH, ABTS and FRAP assays) and, in a thermal-burn model, raised tissue glutathione, superoxide dismutase and catalase. The activity tracks the hydrophilic flavonoid and phenolic fraction, including rutin, narcissin and chlorogenic acid, plus the carotenoids.

All of this is in vitro and animal work, with no human antioxidant-biomarker trial. It is a contributing mechanism in wound healing rather than a benefit of its own.

The evidence is entirely preclinical. Calendula extract loaded into chitosan nanoparticles was cytotoxic to gastric (AGS) and colon (Caco-2) cancer cells through a ROS-driven apoptotic pathway, while sparing normal fibroblasts ^{36Reference 36Ozturk et al. · 2025In vitroIn vitro anticancer efficacy of Calendula officinalis extract-loaded chitosan nanoparticles against gastric and colon cancer cells — in vitroView study →}. Aqueous infusions show antiproliferative activity against several human cell lines in vitro, and a 2025 computational study screened calendula phytochemicals as candidate KRAS inhibitors by docking.

Gap: the effective preparations are chitosan nanoparticles and docking predictions. Neither resembles an infused oil or a tincture, and there are no animal tumour or human data.

This rests on a single rodent study. The flower’s methanol extract and its saponin fraction lowered post-load serum glucose, slowed gastric emptying and protected against ethanol- and indomethacin-induced gastric lesions in rats. The effects were attributed to newly isolated oleanane-type triterpene glycosides, calendasaponins A–D ^{27Reference 27Yoshikawa M et al. · 2001AnimalMedicinal flowersView study →}. The finding is consistent with the traditional internal use for gut inflammation.

Gap: one study, in one species, of an isolated saponin fraction rather than the infusion or tincture the herb is taken as, and neither the glucose nor the gastroprotective endpoint has been replicated.

Toxicity. The Cosmetic Ingredient Review panel found calendula-derived ingredients non-genotoxic and not irritating, sensitising or photosensitising in animal and clinical testing, though possibly mildly irritating to the eye ^{31Reference 31Andersen FA et al. · 2010ReviewFinal report of the Cosmetic Ingredient Review Expert Panel amended safety assessment of Calendula officinalis-derived cosmetic ingredients — [review (safety assessment)]View study →}. Human wound and dermatitis trials report almost no adverse events ^{20,24Reference 20Panahi Y et al. · 2012RCTA randomized comparative trial on the therapeutic efficacy of topical aloe vera and Calendula officinalis on diaper dermatitis in children — [randomised controlled trial]View study →Reference 24Pazhohideh Z et al. · 2018RCTThe effect of Calendula officinalis versus metronidazole on bacterial vaginosis in women: A double-blind randomized controlled trial — [randomised controlled trial]View study →}.

Allergy. Skin sensitisation has been reported, at an unknown frequency ^{34Reference 34Committee on Herbal Medicinal Products ( · 2018ReviewEuropean Union herbal monograph on Calendula officinalis L., flos (EMA/HMPC/437450/2017) — regulatory monographView study →}. In a series of 443 patch-tested patients, about 2% reacted to marigold, often alongside reactions to propolis, fragrances and other daisy-family plants ^{28,29Reference 28Reider N et al. · 2001Clinical trialThe seamy side of natural medicines: contact sensitization to arnica (Arnica montana L.) and marigold (Calendula officinalis L.) — [clinical study (patch-test cohort)]View study →Reference 29Paulsen E et al. · 2002ReviewContact sensitization from Compositae-containing herbal remedies and cosmetics — [review]View study →}. That series tested the whole aerial parts rather than the flowers alone, and calendula flowers contain no sesquiterpene lactones, the usual daisy-family allergens ^{35Reference 35Committee on Herbal Medicinal Products ( · 2018ReviewAssessment report on Calendula officinalis L., flos (EMA/HMPC/603409/2017) — regulatory reviewView study →}.

People allergic to ragweed, chamomile, arnica, echinacea or other daisy-family plants should patch-test before using it widely on the skin. The EU herbal monograph lists daisy-family allergy as a contraindication ^{34Reference 34Committee on Herbal Medicinal Products ( · 2018ReviewEuropean Union herbal monograph on Calendula officinalis L., flos (EMA/HMPC/437450/2017) — regulatory monographView study →}.

Children. The EU herbal monograph does not recommend its products on the skin under 6 years of age, or in the mouth and throat under 12, because of a lack of data ^{34Reference 34Committee on Herbal Medicinal Products ( · 2018ReviewEuropean Union herbal monograph on Calendula officinalis L., flos (EMA/HMPC/437450/2017) — regulatory monographView study →}. The nappy-rash trials were run in infants without reported harm ^{20,21Reference 20Panahi Y et al. · 2012RCTA randomized comparative trial on the therapeutic efficacy of topical aloe vera and Calendula officinalis on diaper dermatitis in children — [randomised controlled trial]View study →Reference 21Sharifi-Heris Z et al. · 2018RCTComparison the effects of topical application of olive and calendula ointments on Children’s diaper dermatitis: A triple-blind randomized clinical trial — [randomised controlled trial]View study →}.

Internal use. Internal use has been studied far less than topical use. In mouse Leydig cells in vitro, calendula extract reduced cell viability and altered steroid production at 150 µg/mL and above ^{33Reference 33Jambor T et al. · 2021In vitroThe effect of Apium graveolens L., Levisticum officinale and Calendula officinalis L. on cell viability, membrane integrity, steroidogenesis, and intercellular communication in mice Leydig cells in vitro — [in vitro study]View study →}.

Interactions. No drug interactions have been reported ^{34Reference 34Committee on Herbal Medicinal Products ( · 2018ReviewEuropean Union herbal monograph on Calendula officinalis L., flos (EMA/HMPC/437450/2017) — regulatory monographView study →}, but none has been formally studied, and there is no CYP450 data.