Marshmallow Root

Marshmallow root (Althaea officinalis) is a traditional demulcent used to soothe irritated throat and reduce dry, irritating cough. There is reasonable evidence it helps symptomatically (soothes throat, reduces cough reflex) but no high-quality clinical evidence that it cures or treats the underlying infection (Bordetella pertussis / whooping cough). If pertussis is suspected you should seek medical care (antibiotics and public-health measures) — marshmallow can only be considered supportive symptom care.

• Demulcent (mucilage) action: Marshmallow root contains large amounts of mucilage (polysaccharides such as rhamnogalacturonans, arabinans, arabinogalactans). When mixed with water these form a viscous gel that coats and soothes irritated mucous membranes in the mouth, throat and upper airways. That coating reduces irritation of sensory nerves and can reduce the cough reflex and the discomfort of a raw throat. European Medicines Agency (EMA)
• Anti-inflammatory and mucoprotective effects: Preclinical and some clinical data and reviews report anti-inflammatory and mucoprotective effects that plausibly reduce throat irritation and dry cough. This is why marshmallow is used traditionally and why regulators accept its traditional use for symptomatic relief of dry cough. Karger

Important clinical caveat: Whooping cough (pertussis) is a bacterial infection caused by Bordetella pertussis. Marshmallow does not kill bacteria or replace antibiotics or public-health measures. Its role is symptomatic — soothing throat and helping the sufferer tolerate coughing fits — not eradicating pertussis.

Common preparations and how they’re used

• Syrup (commercial cough syrups or pharmacy-made): Many clinical evaluations and traditional products use aqueous root extracts in syrups. The EMA assessment and related product information give typical posologies such as 5–10 mL, 3–4 times daily for adults; 2.5–5 mL several times daily for children (age bands vary by product) — check the product label for exact dosing. The monograph also describes syrups prepared from a macerate made from ~5–6 g Althaeae radix per 100 g product and gives spoonful dosing 3–4×/day. European Medicines Agency (EMA)
• Lozenges/Throat pastilles: Slow-dissolving lozenges that contain marshmallow extract soothe the throat directly — follow manufacturer’s directions. Clinical user surveys evaluated lozenges as well. Miloa Academy
• Infusion / macerate (tea): A traditional macerate is made by pouring ~150 mL cool/warm water over 0.5–3 g (depending on recommendation) of comminuted root and steeping (some monographs recommend ≈30 minutes, often at or below 40 °C for macerates). Macerates are typically consumed several times daily. EMA/assessment texts give details for making macerate; typical herbal single doses described range (adolescents/adults) around 3–5 g several times daily for a macerate preparation. pharmacie-homeopathie.com
• Glycerin (glycero-) extracts: Glycerin extracts are commonly used (alcohol-free) for syrups and children’s products — they are preferred when alcohol is to be avoided. Some over-the-counter products use glycerin extracts combined with honey or plantain. Groupe Berkem

How to use safely and practically

• Use as symptomatic relief: Use marshmallow preparations to soothe throat and reduce dry, irritating cough — as an adjunct to standard medical care for pertussis (diagnosis, antibiotics, isolation when required). European Medicines Agency (EMA)
• Follow product label / monograph dosing: Dosing varies by preparation (tea vs syrup vs lozenge vs extract). The EMA/assessment report and traditional monographs give example doses (e.g., syrup 5–10 mL 3–4×/day; macerate 3–5 g several times daily). Always follow product directions or a qualified herbalist/clinician. European Medicines Agency (EMA)
• Children: EMA documents note not recommended below a certain young age (recommendations vary by indication and product; many products advise do not use in children under 3 years or seek medical advice for very young children). Because whooping cough can be severe in infants, seek medical care urgently rather than relying on herbs for infants. Theodora

Practical example (traditional macerate recipe from monograph)

• Pour 150 mL water (≤40 °C) over comminuted marshmallow root (amount depends on desired strength; some monographs discuss 3–5 g macerate). Steep ~30 minutes with stirring; use immediately. Repeat 2–4× daily as needed for throat irritation. (Exact recipes vary — follow product monograph or label.) pharmacie-homeopathie.com

European Medicines Agency (EMA) — community herbal monograph and assessment report: summarizes traditional use, safety and clinical material. EMA notes two clinical studies with marshmallow root syrup involving around 900 children for mouth/throat irritation and associated dry cough — and concludes the traditional use for symptomatic relief is plausible though high-quality trial evidence is limited. This is a central authoritative source for posology and regulatory acceptance of symptomatic use. European Medicines Agency (EMA)

Karger / Complementary Medicine Review (2019 review) — “Marsh Mallow (Althaea officinalis L.) and Its Potency in the Treatment …” — a narrative review of traditional uses, phytochemistry and modern evidence supporting mucilage-mediated symptomatic relief of cough and throat irritation. It summarizes preclinical and clinical data but notes limitations in trial quality. Karger

Non-interventional user surveys and product studies: Prospective, non-interventional surveys and product evaluations report good tolerability and user-reported improvements in dry cough with marshmallow-containing lozenges and syrups (e.g., surveys of ~822 users, and manufacturer-sponsored syrup evaluations). These are supportive but not randomized controlled trials. Miloa Academy

Laboratory and small clinical evaluations: A number of small clinical or experimental studies have tested marshmallow preparations’ mucoadhesive and mucoprotective properties, and some small trials/case series report benefit for irritating cough, or cough induced by ACE-inhibitors. However, I could not find well-powered randomized controlled trials demonstrating marshmallow root eradicates pertussis infection. Reviews and EMA conclude that evidence supports its symptomatic use based on traditional long use + plausible mechanism but lacks large RCTs for infectious disease cure. Academia