Marshmallow (Althaea officinalis) — The Sunlight Experiment

What Is Marshmallow?

Marshmallow (Althaea officinalis) is a tall perennial in the mallow family (Malvaceae), native to the salt marshes and damp meadows of Europe and the Middle East. Its name survives on the confectionery shelf: the original marshmallow sweet was made from the plant’s thick, sweet, mucilaginous root, though today’s candy no longer contains it ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}. That same mucilage — a viscous polysaccharide gel concentrated in the root and, to a lesser degree, the leaf — is the source of the herb’s medicinal reputation as a demulcent.

Marshmallow’s core use is to soothe and protect irritated mucous membranes. Taken internally it coats the lining of the throat, airways and digestive tract, easing dry cough, sore throat and gastrointestinal irritation; applied topically the root and leaf calm inflamed or damaged skin. Modern work confirms the mechanism is largely physical: the mucilage forms a bioadhesive film over inflamed tissue and supports its repair ^{5Reference 5Deters et al. · 2010In vitroAqueous extracts and polysaccharides from marshmallow roots: cellular internalisation and stimulation of cell physiology of human epithelial cells — in vitroView study →}.

Traditional & Modern Uses

Marshmallow and the other mallows were eaten as food in the classical world — the Romans considered it a delicacy, and it is recorded as a foodstuff among the Chinese and Egyptians as well ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}. Pliny’s claim that a daily dose of mallow makes a person “whole of all diseases” is folklore rather than pharmacology, but it captures the plant’s long reputation as a gentle cure-all ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}. Arab physicians applied the leaves as an anti-inflammatory poultice, and in France a root paste (the original pâte de guimauve) was used to soothe sore chests, coughs and hoarseness ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}.

In Western herbal practice marshmallow has long been used for respiratory catarrh, cough, peptic ulcers, inflammation of the mouth and pharynx, cystitis and urethritis, and topically for abscesses, boils and varicose ulcers ^{27Reference 27Barnes et al. · 2007Herbal Medicines (3rd ed.)}. The through-line is its demulcent, soothing action on mucosa and epithelium — the root favoured for the digestive tract, the leaf for the urinary and respiratory tracts ^{25Reference 25Hoffmann · 2003Medical Herbalism: The Science and Practice of Herbal Medicine}. Today it is most familiar as an ingredient in cough syrups, throat lozenges and soothing skin preparations.

Botany & Varieties

Marshmallow belongs to the mallow family (Malvaceae), whose better-known members include okra, cacao, cotton and hibiscus. The genus name Althaea derives from the Greek althaino, “to heal,” and the species epithet officinalis marks its historical status as an official medicinal plant ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}.

It is a perennial reaching to about two metres, with soft, velvety, ovate-cordate leaves toothed at the margin and pale flowers. A long, tapering taproot stores much of the mucilage and other soluble constituents ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}. Marshmallow is distinguished from the common mallow (Malva sylvestris) by the numerous divisions of its outer calyx and by its downy, furry leaves and stems, with flowers paler than the common mallow’s ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}.

Habitat & Distribution

Marshmallow is native to most of Europe and the Middle East, and is naturalised in parts of North America. True to its name, it favours damp, brackish ground — salt marshes, wet meadows and ditches ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}.

Harvesting & Preparation

Both root and leaf are used, with the root generally preferred for the digestive tract and the leaf for the urinary and respiratory tracts ^{25Reference 25Hoffmann · 2003Medical Herbalism: The Science and Practice of Herbal Medicine}. Because the active mucilage is water-soluble and heat-sensitive, marshmallow is traditionally prepared as a cold infusion — the chopped root steeped in cold water — to preserve it, or gently decocted; the root is also boiled with wine or milk, or made into a honey syrup for coughs, which is often preferred for children ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}. A root decoction is mucilaginous enough to serve as an egg substitute in cooking, and the tender leaves can be eaten raw ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}.

Phytochemistry

The defining constituent of marshmallow is its mucilage — a viscous polysaccharide complex (rhamnogalacturonans, arabinogalactans and arabinans) that makes up the largest single fraction of the root and drives the herb’s demulcent and emollient action ^{22Reference 22Xue et al. · 2023ReviewIsolation, structural properties, and bioactivities of polysaccharides from Althaea officinalis Linn.: a review — reviewView study →}. Alongside it sit pectin, the amino acid asparagine, and a suite of leaf flavonoids (kaempferol, quercetin and diosmetin glucosides) responsible for its antimicrobial activity ^{18Reference 18Mehreen et al. · 2016In vitroPhytochemical, antimicrobial, and toxicological evaluation of traditional herbs used to treat sore throat — in vitroView study →}. Modern phytochemical work on the root’s low-molecular-weight fraction has added hypolaetin and its O-sulfoglycosides (including a 4′-O-methylisoscutellarein sulfoglycoside), the coumarin glycoside haploperoside D, and appreciable amounts of glycine betaine (~8% of that fraction) and free proline; the hypolaetin sulfoglycosides are linked to the extract’s hyaluronidase-inhibiting, anti-inflammatory activity ^{6Reference 6Sendker et al. · 2017In vitroPhytochemical characterization of low molecular weight constituents from marshmallow roots and inhibiting effects of the aqueous extract on human hyaluronidase-1 — in vitroView study →}.

Constituent Summary

Amounts are percent of the dried root unless noted; mucilage figures vary with reporting method (older “total mucilage” assays give ~18–35%, isolated water-soluble polysaccharide ~5–12%) ^{25Reference 25Hoffmann · 2003Medical Herbalism: The Science and Practice of Herbal Medicine}.

Grouped by class · 5 compounds

Mucilage1 compound1 with data

MucilageMucilage~5–35% (root)

Polysaccharide1 compound1 with data

PolysaccharidePectinup to ~11–35%

Amino Acid1 compound1 with data

Amino AcidAsparagine~1–2%

Flavonoid2 compounds2 with data

FlavonoidHypolaetinNo Data (root, low-MW fraction)

FlavonoidFlavonoidsNo Data (leaf)

Root

Mucilage (18–35%) ^{25Reference 25Hoffmann · 2003Medical Herbalism: The Science and Practice of Herbal Medicine}
Starch
Pectin (up to ~35%) ^{25Reference 25Hoffmann · 2003Medical Herbalism: The Science and Practice of Herbal Medicine}
Oil
Sugar
Asparagine (1–2%) ^{25Reference 25Hoffmann · 2003Medical Herbalism: The Science and Practice of Herbal Medicine}
Cellulose
Glutinous matter ^{26Reference 26Grieve · 1931A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.htmlView study →}

Leaves

Mucilage
- Including low molecular weight D-glucan
Flavonoids
- Kaempferol
- Quercetin
- Diosmetin glucosides
Scopoletin
Polyphenolic acids
- Syringic acid
- Caffeic acid
- Salicylic acid
- Vanillic acid
- p-Coumaric acid

Pharmacology & Research

Marshmallow (Althaea officinalis) has a modest but coherent literature dominated by one mechanism: its root and leaf mucilage forms a bioadhesive film that physically soothes irritated mucosa. The evidence tier is mostly preclinical — cell and animal work — anchored by human observational data (large consumer surveys of dry-cough preparations) and a handful of small clinical trials in which marshmallow is a component of a combination product rather than the sole active. The strongest and most interesting emerging signals sit slightly off the traditional demulcent axis: anti-inflammatory and antioxidant activity of standardised root extract on immune and endothelial cells ^{9,10Reference 9Bonaterra et al. · 2020In vitroAnti-inflammatory and anti-oxidative effects of Phytohustil and root extract of Althaea officinalis L. on macrophages — in vitroView study →Reference 10Bonaterra et al. · 2022In vitroPhytohustil and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve migratory capacity of endothelial cells — in vitroView study →}, and a small pilot trial in childhood atopic dermatitis ^{15Reference 15Naseri et al. · 2021RCTEffect of topical marshmallow (Althaea officinalis) on atopic dermatitis in children: a pilot double-blind active-controlled clinical trial — randomisedView study →}. No large placebo-controlled trial of marshmallow monotherapy exists for any indication, and results are heavily preparation-dependent — an aqueous mucilage-rich extract behaves very differently from an ethanolic or a flower extract, so findings rarely transfer across forms.

What the evidence supports

Best-supported: demulcent soothing of dry cough and throat irritation, backed by codeine-comparable antitussive activity in animals ^{2,3,4Reference 2Šutovská et al. · 2009AnimalPossible mechanisms of dose-dependent cough suppressive effect of Althaea officinalis rhamnogalacturonan — animal (guinea pig in vivo)View study →Reference 3Šutovská et al. · 2011AnimalAntitussive activity of Althaea officinalis L. polysaccharide rhamnogalacturonan in guinea pigs with airways inflammation — animal in vivoView study →Reference 4Šutovská et al. · 2007AnimalThe antitussive activity of polysaccharides from Althaea officinalis L., varView study →}, human consumer surveys ^{1Reference 1Fink et al. · 2018ObservationalMarshmallow root extract for the treatment of irritative cough: two surveys on users’ view on effectiveness and tolerability — observational/cohort surveyView study →}, and mucosal-film/cell-repair mechanisms in vitro ^{5,6Reference 5Deters et al. · 2010In vitroAqueous extracts and polysaccharides from marshmallow roots: cellular internalisation and stimulation of cell physiology of human epithelial cells — in vitroView study →Reference 6Sendker et al. · 2017In vitroPhytochemical characterization of low molecular weight constituents from marshmallow roots and inhibiting effects of the aqueous extract on human hyaluronidase-1 — in vitroView study →}; anti-inflammatory and antioxidant activity of root extract on macrophages and endothelial cells ^{9,10Reference 9Bonaterra et al. · 2020In vitroAnti-inflammatory and anti-oxidative effects of Phytohustil and root extract of Althaea officinalis L. on macrophages — in vitroView study →Reference 10Bonaterra et al. · 2022In vitroPhytohustil and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve migratory capacity of endothelial cells — in vitroView study →}.
Emerging, worth watching: topical wound healing and skin soothing, including a small atopic-dermatitis pilot trial ^{13,15Reference 13Mohsenikia et al. · 2020AnimalAlthaea officinalis improves wound healing in rats: a stereological study — animal (rat)View study →Reference 15Naseri et al. · 2021RCTEffect of topical marshmallow (Althaea officinalis) on atopic dermatitis in children: a pilot double-blind active-controlled clinical trial — randomisedView study →}; gastroprotection in rodent ulcer models ^{11,17Reference 11Hage-Sleiman et al. · 2011AnimalPharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon — animal (rat)View study →Reference 17Zaghlool et al. · 2019AnimalGastro-protective and anti-oxidant potential of Althaea officinalis and Solanum nigrum on pyloric ligation/indomethacin-induced ulceration in rats — animal (rat)View study →}.
Mechanistically thin: hypoglycaemic and skin-depigmenting claims rest on single, old, or in-vitro-only studies ^{16,20Reference 16Kobayashi et al. · 2002In vitroInhibitory mechanism of an extract of Althaea officinalis L. on endothelin-1-induced melanocyte activation — in vitroView study →Reference 20Tomoda et al. · 1987AnimalHypoglycemic activity of twenty plant mucilages and three modified products — animal (mice)View study →}.
The caveat: almost entirely preclinical for internal use; human trials are small, combination-product, or survey-based, and there is no standardised monotherapy dose.

Evidence by indicationStrength of support

Demulcent & AntitussiveProven

80%

Anti-InflammatoryPromising

66%

AntioxidantPromising

61%

Wound HealingPromising

57%

Skin Soothing (atopic Dermatitis)Promising

54%

GastroprotectivePromising

52%

AntibacterialPromising

47%

HepatoprotectiveShaky

41%

HypoglycaemicShaky

29%

1. Demulcent & antitussive

Marshmallow’s flagship action is demulcent: its mucilage — a viscous polysaccharide complex (chiefly rhamnogalacturonan-type acidic polysaccharides) — forms a bioadhesive layer over inflamed oropharyngeal and gastrointestinal mucosa, physically shielding it and supporting repair ^{5Reference 5Deters et al. · 2010In vitroAqueous extracts and polysaccharides from marshmallow roots: cellular internalisation and stimulation of cell physiology of human epithelial cells — in vitroView study →}. In guinea-pig and cat models, isolated root rhamnogalacturonan suppressed citric-acid- and mechanically-induced cough dose-dependently, with efficacy comparable to codeine and, unlike codeine, negligible impact on expectoration ^{2,3,4Reference 2Šutovská et al. · 2009AnimalPossible mechanisms of dose-dependent cough suppressive effect of Althaea officinalis rhamnogalacturonan — animal (guinea pig in vivo)View study →Reference 3Šutovská et al. · 2011AnimalAntitussive activity of Althaea officinalis L. polysaccharide rhamnogalacturonan in guinea pigs with airways inflammation — animal in vivoView study →Reference 4Šutovská et al. · 2007AnimalThe antitussive activity of polysaccharides from Althaea officinalis L., varView study →}; the effect appears to act through serotonergic 5-HT₂ receptors rather than bronchodilation ^{2Reference 2Šutovská et al. · 2009AnimalPossible mechanisms of dose-dependent cough suppressive effect of Althaea officinalis rhamnogalacturonan — animal (guinea pig in vivo)View study →}. In vitro, aqueous root extract is internalised by epithelial cells and upregulates genes for adhesion, extracellular matrix and cytokine release, stimulating mucosal regeneration ^{5Reference 5Deters et al. · 2010In vitroAqueous extracts and polysaccharides from marshmallow roots: cellular internalisation and stimulation of cell physiology of human epithelial cells — in vitroView study →}. Human data are observational: two prospective surveys of 822 users of an aqueous root-extract lozenge/syrup (STW42) reported rapid symptom relief in dry cough — often within 10 minutes — with very good tolerability ^{1Reference 1Fink et al. · 2018ObservationalMarshmallow root extract for the treatment of irritative cough: two surveys on users’ view on effectiveness and tolerability — observational/cohort surveyView study →}, and marshmallow root is an active component in multi-ingredient throat sprays and formulations shown effective in controlled trials ^{7,21Reference 7Roventa et al. · 2023RCTEffectiveness and tolerability of Ectoin mouth and throat spray Althaea honey (ERS09) for sore throat — randomised, active-controlled trialView study →Reference 21Popovych et al. · 2019RCTRandomized, open-label, multicenter comparative study of BNO 1030 extract (containing marshmallow root) in acute non-bacterial tonsillitis in children — randomised (combination product)View study →}. A 2020 review concluded the animal and clinical evidence supports use in dry cough, strongest in combination products ^{8Reference 8Mahboubi · 2020ReviewMarsh mallow (Althaea officinalis L.) and its potency in the treatment of cough — reviewView study →}.

Gap: no placebo-controlled RCT of marshmallow monotherapy; the best human evidence is survey-based or from combination products, so the herb’s independent effect size is unquantified.

2. Anti-inflammatory

Standardised root extract (a component of the cough product Phytohustil) reduced lipopolysaccharide-induced release of TNF-α and IL-6 in human macrophages, matching or exceeding diclofenac, and improved macrophage migratory capacity without cytotoxicity ^{9Reference 9Bonaterra et al. · 2020In vitroAnti-inflammatory and anti-oxidative effects of Phytohustil and root extract of Althaea officinalis L. on macrophages — in vitroView study →}; a companion study showed the same extract cut interleukin-6 release and improved wound-closure in human endothelial cells ^{10Reference 10Bonaterra et al. · 2022In vitroPhytohustil and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve migratory capacity of endothelial cells — in vitroView study →}. In rats, aqueous flower extract significantly reduced both acute (carrageenan) and chronic (formalin) inflammation across all tested doses ^{11Reference 11Hage-Sleiman et al. · 2011AnimalPharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon — animal (rat)View study →}. Root extract also inhibits human hyaluronidase-1 in vitro (IC₅₀ ≈ 7.7 mg/mL) and downregulates its expression in keratinocytes, a mechanism relevant to inflamed buccal tissue ^{6Reference 6Sendker et al. · 2017In vitroPhytochemical characterization of low molecular weight constituents from marshmallow roots and inhibiting effects of the aqueous extract on human hyaluronidase-1 — in vitroView study →}. The flower flavonoids also inhibit NF-κB-linked signalling in mechanistic work ^{11Reference 11Hage-Sleiman et al. · 2011AnimalPharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon — animal (rat)View study →}.

Gap: all evidence is in vitro or rodent; the human-relevant effect is inferred from cell models of a proprietary extract, with no clinical anti-inflammatory endpoint measured.

3. Antioxidant

Antioxidant activity is documented consistently but only preclinically. Root extract protected human macrophages and endothelial cells against hydrogen-peroxide-induced cytotoxicity and lowered intracellular reactive oxygen species ^{9,10Reference 9Bonaterra et al. · 2020In vitroAnti-inflammatory and anti-oxidative effects of Phytohustil and root extract of Althaea officinalis L. on macrophages — in vitroView study →Reference 10Bonaterra et al. · 2022In vitroPhytohustil and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve migratory capacity of endothelial cells — in vitroView study →}. An isolated acidic root polysaccharide (639 kDa, ~51% galacturonic acid) showed appreciable radical-scavenging capacity in chemical assays ^{12Reference 12Karimi et al. · 2021In vitroPolysaccharide extracted from Althaea officinalis L. root: structural, rheological and antioxidant properties — in vitroView study →}. In rodent ulcer, carcinogenesis and nicotine-induced lung-injury models, marshmallow extracts raised endogenous antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) and reduced lipid peroxidation ^{17,19,23Reference 17Zaghlool et al. · 2019AnimalGastro-protective and anti-oxidant potential of Althaea officinalis and Solanum nigrum on pyloric ligation/indomethacin-induced ulceration in rats — animal (rat)View study →Reference 19Wang et al. · 2023AnimalProtective effects of Althaea officinalis L. extract against N-diethylnitrosamine-induced hepatocellular carcinoma in male Wistar rats — animal (rat)View study →Reference 23Kara et al. · 2026AnimalProtective effect of Althaea officinalis on nicotine-induced lung injury — animal (rat)View study →}.

Gap: all data are chemical-assay, cell or animal; antioxidant capacity in vitro is a weak predictor of clinical benefit, and no human biomarker study exists.

4. Wound healing

Two rat studies support topical use. A stereological study found 5% and 10% marshmallow gels increased fibroblast populations, dermal vessel diameter and — at 10% — collagen synthesis versus vehicle and untreated controls ^{13Reference 13Mohsenikia et al. · 2020AnimalAlthaea officinalis improves wound healing in rats: a stereological study — animal (rat)View study →}. A separate excision-wound study reported significantly faster closure with hydroalcoholic leaf extract, attributed partly to activity against gram-positive bacteria that cause secondary wound infection ^{14Reference 14Rezaei et al. · 2015In vitroEvaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound — animal/in vitroView study →}. The proposed mechanisms — fibroblast activation, anti-inflammatory and antioxidant effects — align with the cell-migration data above ^{10,13Reference 10Bonaterra et al. · 2022In vitroPhytohustil and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve migratory capacity of endothelial cells — in vitroView study →Reference 13Mohsenikia et al. · 2020AnimalAlthaea officinalis improves wound healing in rats: a stereological study — animal (rat)View study →}.

Gap: rodent-only, topical, small; no controlled human wound-healing trial, and the antibacterial contribution is limited to gram-positive organisms ^{14Reference 14Rezaei et al. · 2015In vitroEvaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound — animal/in vitroView study →}.

5. Skin soothing (atopic dermatitis)

The one internal human efficacy signal for skin is a pilot double-blind, active-controlled trial in 22 children with mild-to-moderate atopic dermatitis: a 1% Althaea officinalis ointment reduced SCORAD severity significantly and, in this small sample, more than 1% hydrocortisone ^{15Reference 15Naseri et al. · 2021RCTEffect of topical marshmallow (Althaea officinalis) on atopic dermatitis in children: a pilot double-blind active-controlled clinical trial — randomisedView study →}. The trial paired the clinical arm with in-silico docking suggesting flavonoid glycosides bind TNF-α, IL-6 and phosphodiesterase-4 targets ^{15Reference 15Naseri et al. · 2021RCTEffect of topical marshmallow (Althaea officinalis) on atopic dermatitis in children: a pilot double-blind active-controlled clinical trial — randomisedView study →}. Separately, root extract inhibited endothelin-1-induced melanocyte activation in vitro, pointing to a possible anti-hyperpigmentation and skin-calming role via suppressed MAPK signalling ^{16Reference 16Kobayashi et al. · 2002In vitroInhibitory mechanism of an extract of Althaea officinalis L. on endothelin-1-induced melanocyte activation — in vitroView study →}.

Gap: the clinical evidence is a single underpowered (n=22) active-controlled pilot with no placebo arm; the mechanistic support is docking and cell-line only, and the depigmentation finding is a single cosmetic-science study.

6. Gastroprotective

In a rat pyloric-ligation/indomethacin ulcer model, oral root extract pretreatment for 14 days reduced ulcer number and index, curbed acid and pepsin output, and restored mucosal antioxidant and protective factors, alongside omeprazole and misoprostol comparators ^{17Reference 17Zaghlool et al. · 2019AnimalGastro-protective and anti-oxidant potential of Althaea officinalis and Solanum nigrum on pyloric ligation/indomethacin-induced ulceration in rats — animal (rat)View study →}. Aqueous flower extract likewise showed significant antiulcer activity in an ethanol-induced gastric ulcer model at 50–250 mg/kg, with no adverse effect on liver enzymes ^{11Reference 11Hage-Sleiman et al. · 2011AnimalPharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon — animal (rat)View study →}. The protection is attributed to combined antioxidant, mucosal-coating and antihistamine-like actions ^{11,17Reference 11Hage-Sleiman et al. · 2011AnimalPharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon — animal (rat)View study →Reference 17Zaghlool et al. · 2019AnimalGastro-protective and anti-oxidant potential of Althaea officinalis and Solanum nigrum on pyloric ligation/indomethacin-induced ulceration in rats — animal (rat)View study →}.

Gap: rodent-only, two independent models; the demulcent mucosal-coating rationale is plausible for humans but untested clinically.

7. Antibacterial

Activity is real but narrow. Leaf and flower flavonoids showed in vitro activity against multidrug-resistant Staphylococcus aureus in a screen of herbs used for sore throat ^{18Reference 18Mehreen et al. · 2016In vitroPhytochemical, antimicrobial, and toxicological evaluation of traditional herbs used to treat sore throat — in vitroView study →}, and hydroalcoholic leaf extract inhibited gram-positive strains (including S. aureus and Listeria) but was ineffective against gram-negative organisms such as Pseudomonas aeruginosa and Escherichia coli ^{14Reference 14Rezaei et al. · 2015In vitroEvaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound — animal/in vitroView study →}.

Gap: entirely in vitro, restricted to gram-positive bacteria; the herb is not a systemic antimicrobial and any topical use would need pairing with a gram-negative-active agent ^{14Reference 14Rezaei et al. · 2015In vitroEvaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound — animal/in vitroView study →}.

8. Hepatoprotective

One rat study of N-diethylnitrosamine-induced hepatocellular carcinogenesis found flower extract (250 and 500 mg/kg), particularly co-administered with silymarin, normalised liver enzymes, improved serum antioxidant indices, lowered pro-inflammatory cytokines and shifted apoptotic markers (Bax/Bcl-2/p53, PI3K/Akt/mTOR) toward protection of normal hepatocytes ^{19Reference 19Wang et al. · 2023AnimalProtective effects of Althaea officinalis L. extract against N-diethylnitrosamine-induced hepatocellular carcinoma in male Wistar rats — animal (rat)View study →}.

Gap: a single animal study where the clearest effects appear in combination with silymarin; marshmallow’s independent hepatoprotective contribution is unresolved and there is no human data.

9. Hypoglycaemic

The hypoglycaemic claim rests on a single 1987 study in which plant mucilages, including that of marshmallow, lowered blood glucose in non-diabetic mice ^{20Reference 20Tomoda et al. · 1987AnimalHypoglycemic activity of twenty plant mucilages and three modified products — animal (mice)View study →}. No replication, no diabetic model, and no human data have followed.

Gap: one old animal study in non-diabetic animals; this is essentially a mechanistic curiosity, not a supported indication, and any additive effect with glucose-lowering drugs is theoretical.

Mechanisms

Mechanism	Drives	Key compounds
Bioadhesive mucilage film on mucosa (physical barrier + cell-repair signalling)	demulcentantitussivegastroprotective	mucilage / rhamnogalacturonan (polysaccharide fraction)
5-HT₂ receptor–mediated cough-reflex suppression	antitussive	rhamnogalacturonan fraction
TNF-α, IL-6 ↓ / NF-κB-linked signalling ↓	anti-inflammatory	leaf flavonoids, quercetin, kaempferol
ROS scavenging; SOD, CAT, GPx ↑	antioxidantgastroprotectivehepatoprotective	caffeic acid, acidic root polysaccharide
Hyaluronidase-1 inhibition	mucosal anti-inflammatory	hypolaetin sulfoglycosides
Fibroblast activation, collagen synthesis, epithelial migration	wound healing	extract-level (polysaccharide + phenolics)
Endothelin-1 secretion & MAPK ↓	skin calming / depigmentation	extract-level

Clinical trials

Registered and published clinical work is limited and mostly on marshmallow-containing combination products, not the herb alone: one completed device trial of an Althaea-honey throat spray (NCT04203810, n≈194) and small published trials of a combination tonsillitis extract and a topical atopic-dermatitis ointment; the remaining human evidence is consumer-survey rather than randomised.

Completed	Planned	Terminated	Preclinical
3(2 combination-product RCTs + 1 pilot ointment RCT)	0	0	~20

Last checked: July 2026.

Dosage

Marshmallow’s human trials use proprietary aqueous extracts, sprays and topical ointments rather than a weighed herb dose, so the figures below are what was studied, not conversions to dried-herb weight. These are research doses, not recommendations.

Indication	Preparation	Dose	Est. dried-herb equivalent	Source
Dry cough / throat irritation	Aqueous root-extract lozenge/syrup (STW42)	As-marketed OTC dosing over ~7 days	— (proprietary aqueous extract, no marker %)	^{1Reference 1Fink et al. · 2018ObservationalMarshmallow root extract for the treatment of irritative cough: two surveys on users’ view on effectiveness and tolerability — observational/cohort surveyView study →}
Sore throat / pharyngitis	Althaea-honey throat spray (ERS09)	Sprayed, 7 ± 2 days	— (device/spray)	^{7Reference 7Roventa et al. · 2023RCTEffectiveness and tolerability of Ectoin mouth and throat spray Althaea honey (ERS09) for sore throat — randomised, active-controlled trialView study →}
Atopic dermatitis (children)	Topical 1% ointment	Twice daily for 1 wk, then 3×/wk for 3 wk	— (topical)	^{15Reference 15Naseri et al. · 2021RCTEffect of topical marshmallow (Althaea officinalis) on atopic dermatitis in children: a pilot double-blind active-controlled clinical trial — randomisedView study →}

Human trial doses were proprietary aqueous extracts, sprays or topical products with no stated marker-compound percentage, so no reliable back-conversion to dried-herb weight is possible — equivalents are left as ”—” rather than invented.

Traditional Dosage

Traditional use is of the whole root or leaf, taken as a cold infusion, tincture or syrup — a food-like demulcent rather than a titrated extract.

System	Preparation	Dose
Western herbal	Liquid extract (1:2)	2–40 mL/week
Western herbal	Cold-infused root (cold maceration)	2–4 g dried root steeped cold, up to 3×/day
Western herbal	Root decoction / honey syrup	Traditional demulcent preparation, especially for children

Safety & Pregnancy

Marshmallow is well tolerated and suitable for long-term use; its only real practical caution is that the mucilage can slow the absorption of other oral drugs, so doses should be separated.

Safety at a glance

Low / no toxicity

Well tolerated. Large consumer surveys of root-extract preparations report only rare, minor adverse events.
Slows drug absorption. The mucilage coats the gut — take marshmallow at least 1–2 hours apart from other oral medications.
Interactions unstudied. No CYP450 or transporter testing; absence of reported problems is not clearance.
Gram-positive only. Its antibacterial action does not cover gram-negative infection — don’t rely on it there.

Full safety & interactions detail

Marshmallow is well tolerated and classified as safe for long-term use; the German pharmacopoeial tradition and large consumer surveys of aqueous root-extract preparations report only rare, minor adverse events ^{1Reference 1Fink et al. · 2018ObservationalMarshmallow root extract for the treatment of irritative cough: two surveys on users’ view on effectiveness and tolerability — observational/cohort surveyView study →}. The main practical concern is not toxicity but absorption: the mucilage forms a viscous coating in the gut that can slow or reduce the uptake of other oral medications, supplements and herbs, so marshmallow is best taken at least 1–2 hours apart from other oral drugs ^{25Reference 25Hoffmann · 2003Medical Herbalism: The Science and Practice of Herbal Medicine}. No hepatotoxicity was seen in animals given the flower extract for a month ^{11Reference 11Hage-Sleiman et al. · 2011AnimalPharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon — animal (rat)View study →}, and the acute toxicity of the root extract in mice is low ^{24Reference 24Benbassat et al. · 2013In vitroDevelopment and evaluation of novel lozenges containing marshmallow root extract — in vitro/pharmaceuticalView study →}. A theoretical additive effect with blood-glucose-lowering agents follows from a single old animal study ^{20Reference 20Tomoda et al. · 1987AnimalHypoglycemic activity of twenty plant mucilages and three modified products — animal (mice)View study →}, and marshmallow’s antibacterial action is limited to gram-positive organisms and should not be relied on against gram-negative infection ^{14Reference 14Rezaei et al. · 2015In vitroEvaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound — animal/in vitroView study →}. Herb–drug interactions beyond the physical absorption effect have not been formally studied — no CYP450 or transporter interaction has been tested, so the absence of reported problems should not be read as clearance.

Pregnancy & Lactation

Not established in pregnancy Not established in lactation

Not specifically researched. No controlled human or animal reproductive-safety studies of Althaea officinalis were identified, and pharmacopoeial sources record no specific reproductive toxicity — but absence of adverse reports is not evidence of safety. As a bland demulcent it is generally regarded as low-risk; the same absorption caveat applies, so separate it from any medication taken during pregnancy or lactation, and use it under professional guidance.

Synergy

As a vulnerary, marshmallow is best combined with herbs or essential oils that are active against gram-negative bacteria, since its own antibacterial effect is confined to gram-positive organisms and secondary wound infection is often gram-negative ^{14Reference 14Rezaei et al. · 2015In vitroEvaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound — animal/in vitroView study →}. For cough, marshmallow root is frequently formulated with other demulcent and antitussive herbs — ivy (Hedera helix), Zataria multiflora and ginger among them — and reviews note that these combination products carry the strongest clinical evidence ^{8Reference 8Mahboubi · 2020ReviewMarsh mallow (Althaea officinalis L.) and its potency in the treatment of cough — reviewView study →}.

References

Fink, C., Schmidt, M., & Kraft, K. (2018). Marshmallow root extract for the treatment of irritative cough: two surveys on users’ view on effectiveness and tolerability — observational/cohort survey. Complementary Medicine Research. https://pubmed.ncbi.nlm.nih.gov/30064132/
Šutovská, M., Nosáľová, G., Šutovský, J., Franová, S., Prisenžňáková, Ľ., & Capek, P. (2009). Possible mechanisms of dose-dependent cough suppressive effect of Althaea officinalis rhamnogalacturonan — animal (guinea pig in vivo). International Journal of Biological Macromolecules. https://pubmed.ncbi.nlm.nih.gov/19447256/
Šutovská, M., Capek, P., Franová, S., Joskova, M., Šutovský, J., Marcinek, J., & Kalman, M. (2011). Antitussive activity of Althaea officinalis L. polysaccharide rhamnogalacturonan in guinea pigs with airways inflammation — animal in vivo. Bratislava Medical Journal. https://pubmed.ncbi.nlm.nih.gov/22372330/
Šutovská, M., Nosáľová, G., Franová, S., & Kardošová, A. (2007). The antitussive activity of polysaccharides from Althaea officinalis L., var. Robusta — animal in vivo (cats). Bratislava Medical Journal. https://pubmed.ncbi.nlm.nih.gov/17685009/
Deters, A., Zippel, J., Hellenbrand, N., Pappai, D., Possemeyer, C., & Hensel, A. (2010). Aqueous extracts and polysaccharides from marshmallow roots: cellular internalisation and stimulation of cell physiology of human epithelial cells — in vitro. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/19799989/
Sendker, J., Böker, I., Lengers, I., et al. (2017). Phytochemical characterization of low molecular weight constituents from marshmallow roots and inhibiting effects of the aqueous extract on human hyaluronidase-1 — in vitro. Journal of Natural Products. https://pubmed.ncbi.nlm.nih.gov/28128955/
Roventa, D. L. C., Pieper-Fürst, U., Acikel, C., Santos, D., Sent, U., & Mösges, R. (2023). Effectiveness and tolerability of Ectoin mouth and throat spray Althaea honey (ERS09) for sore throat — randomised, active-controlled trial. Journal of Clinical Medicine. https://pubmed.ncbi.nlm.nih.gov/37762768/
Mahboubi, M. (2020). Marsh mallow (Althaea officinalis L.) and its potency in the treatment of cough — review. Complementary Medicine Research. https://pubmed.ncbi.nlm.nih.gov/31770755/
Bonaterra, G. A., Bronischewski, K., Hunold, P., et al. (2020). Anti-inflammatory and anti-oxidative effects of Phytohustil and root extract of Althaea officinalis L. on macrophages — in vitro. Frontiers in Pharmacology. https://pubmed.ncbi.nlm.nih.gov/32256361/
Bonaterra, G. A., Schmitt, J., Schneider, K., et al. (2022). Phytohustil and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve migratory capacity of endothelial cells — in vitro. Frontiers in Pharmacology. https://pubmed.ncbi.nlm.nih.gov/36569306/
Hage-Sleiman, R., Mroueh, M., & Daher, C. F. (2011). Pharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon — animal (rat). Pharmaceutical Biology. https://pubmed.ncbi.nlm.nih.gov/21281251/
Karimi, S., Ghanbarzadeh, B., Roufegarinejad, L., & Falcone, P. M. (2021). Polysaccharide extracted from Althaea officinalis L. root: structural, rheological and antioxidant properties — in vitro. Carbohydrate Research. https://pubmed.ncbi.nlm.nih.gov/34597979/
Mohsenikia, M., Rafiee, S., Rozei, L. S., et al. (2020). Althaea officinalis improves wound healing in rats: a stereological study — animal (rat). Drug Discoveries & Therapeutics. https://pubmed.ncbi.nlm.nih.gov/33116035/
Rezaei, M., Dadgar, Z., Noori-Zadeh, A., Mesbah-Namin, S. A., Pakzad, I., & Davodian, E. (2015). Evaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound — animal/in vitro. Avicenna Journal of Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/25949951/
Naseri, V., Chavoshzadeh, Z., Mizani, A., et al. (2021). Effect of topical marshmallow (Althaea officinalis) on atopic dermatitis in children: a pilot double-blind active-controlled clinical trial — randomised. Phytotherapy Research. https://pubmed.ncbi.nlm.nih.gov/33034099/
Kobayashi, A., Hachiya, A., Ohuchi, A., Kitahara, T., & Takema, Y. (2002). Inhibitory mechanism of an extract of Althaea officinalis L. on endothelin-1-induced melanocyte activation — in vitro. Biological & Pharmaceutical Bulletin. https://pubmed.ncbi.nlm.nih.gov/11853172/
Zaghlool, S. S., Abo-Seif, A. A., Rabeh, M. A., Abdelmohsen, U. R., & Messiha, B. A. S. (2019). Gastro-protective and anti-oxidant potential of Althaea officinalis and Solanum nigrum on pyloric ligation/indomethacin-induced ulceration in rats — animal (rat). Antioxidants (Basel). https://pubmed.ncbi.nlm.nih.gov/31731465/
Mehreen, A., Waheed, M., Liaqat, I., & Arshad, N. (2016). Phytochemical, antimicrobial, and toxicological evaluation of traditional herbs used to treat sore throat — in vitro. BioMed Research International. https://pubmed.ncbi.nlm.nih.gov/27429983/
Wang, Z., et al. (2023). Protective effects of Althaea officinalis L. extract against N-diethylnitrosamine-induced hepatocellular carcinoma in male Wistar rats — animal (rat). Food Science & Nutrition. https://pubmed.ncbi.nlm.nih.gov/37576045/
Tomoda, M., Shimizu, N., Oshima, Y., Takahashi, M., Murakami, M., & Hikino, H. (1987). Hypoglycemic activity of twenty plant mucilages and three modified products — animal (mice). Planta Medica. https://pubmed.ncbi.nlm.nih.gov/3575513/
Popovych, V., Koshel, I., Malofiichuk, A., et al. (2019). Randomized, open-label, multicenter comparative study of BNO 1030 extract (containing marshmallow root) in acute non-bacterial tonsillitis in children — randomised (combination product). American Journal of Otolaryngology. https://pubmed.ncbi.nlm.nih.gov/30554882/
Xue, T., et al. (2023). Isolation, structural properties, and bioactivities of polysaccharides from Althaea officinalis Linn.: a review — review. International Journal of Biological Macromolecules. https://pubmed.ncbi.nlm.nih.gov/37245776/
Kara, O., et al. (2026). Protective effect of Althaea officinalis on nicotine-induced lung injury — animal (rat). Complementary Medicine Research. https://pubmed.ncbi.nlm.nih.gov/42348476/
Benbassat, N., Kostova, B., Nikolova, I., & Rachev, D. (2013). Development and evaluation of novel lozenges containing marshmallow root extract — in vitro/pharmaceutical. Pakistan Journal of Pharmaceutical Sciences. https://pubmed.ncbi.nlm.nih.gov/24191313/
Hoffmann, D. (2003). Medical Herbalism: The Science and Practice of Herbal Medicine. Rochester, VT: Healing Arts Press. (pp. 526–527).
Grieve, M. (1931). A Modern Herbal — Mallow (Marsh). https://www.botanical.com/botanical/mgmh/m/mallow07.html
Barnes, J., Anderson, L. A., & Phillipson, J. D. (2007). Herbal Medicines (3rd ed.). London: Pharmaceutical Press. (pp. 418–420).