Yao Shu Kui
StarAlthaea officinalis L.
☯ TCM Properties
Clears Heat and Cools the Blood; Moistens dryness and protects mucous membranes; Promotes Urination and Relieves Stranguria; Clears Heat and Resolves Toxicity; Moistens the Lungs and Stops Cough; Generates Fluids
Traditional Chinese Uses
Yao Shu Kui (marshmallow root, althaea) is a cool, sweet, mucilaginous herb used in Chinese medicine to soothe and protect irritated mucous membranes throughout the body. Its high mucilage content creates a protective coating on inflamed respiratory, digestive, and urinary tract tissues, making it effective for dry cough, sore throat, gastric irritation, and urinary burning. Gentle and food-safe, it is appropriate for long-term soothing support in inflammatory and drying conditions across multiple organ systems.
Western Herbalism Properties
Botanical Description
Althaea officinalis, the marshmallow, is a perennial herbaceous plant in the family Malvaceae, native to brackish marshes, riverbanks, and damp meadows across Europe, western Asia, and North Africa. It grows 1-2 meters tall from a thick, fleshy, branching white taproot rich in mucilage. The erect, downy stems bear alternate, ovate to triangular, softly velvety leaves with 3-5 shallow lobes and irregularly toothed margins. Five-petaled pale-pink to nearly white flowers, 2-5 cm across, are borne in axillary clusters and feature an epicalyx of 6-9 bracteoles below the calyx and a central column of fused stamens. The fruit is a schizocarp of many flat, kidney-shaped mericarps. All parts are notably mucilaginous.
Active Constituents
Mucilage polysaccharides (rhamnogalacturonans, arabinogalactans, arabinans, glucans)
Acidic and neutral heteropolysaccharidesConcentration: Approximately 5-35% of dry root weight (highest in autumn-harvested roots)
The primary active fraction. These high-molecular-weight, water-soluble polysaccharides form a viscous, bioadhesive film over oral, pharyngeal and gastrointestinal mucosa, protecting irritated epithelium from mechanical and microbial stimuli. This physical demulcent barrier accounts for the antitussive (dry cough), throat-soothing and gastroprotective effects and stimulates epithelial cell regeneration.
Flavonoids (hypolaetin 8-glucoside, kaempferol, quercetin and isoquercitrin glycosides)
Flavonoid glycosidesConcentration: Minor constituents of root and flower
Contribute antioxidant and anti-inflammatory activity, supporting the soothing effect on inflamed mucous membranes.
Phenolic acids (caffeic, p-coumaric, ferulic, syringic, chlorogenic acids)
Hydroxycinnamic / hydroxybenzoic acidsConcentration: Minor constituents
Provide antioxidant and mild antimicrobial activity and add to the anti-inflammatory profile of the extract.
Scopoletin and other coumarins
CoumarinsConcentration: Trace constituents
Contribute mild anti-inflammatory and spasmolytic activity.
Phytosterols
SterolsConcentration: Minor constituents
Contribute to the anti-inflammatory activity of the root extract.
Starch and pectin
Storage and structural polysaccharidesConcentration: Starch ~25-35%; pectin ~11%
Bulk polysaccharides that add to the demulcent, emollient and gentle bulking properties of the root.
Asparagine and other free amino acids
Amino acidsConcentration: Minor constituents
Nutritive components with mild emollient value; asparagine was historically isolated from marshmallow root.
Tannins
PolyphenolsConcentration: Low levels
Provide mild astringent and antimicrobial activity that complements the soothing mucilage.
⚠ Drug Interactions
Concurrently taken oral medications (general)
The viscous mucilage can coat the gastrointestinal mucosa and physically slow or reduce the absorption of drugs taken at the same time. This is a class effect of demulcent, mucilage-rich herbs rather than a specific pharmacokinetic interaction.
Clinical note: Separate marshmallow intake from other oral medications by at least 1-2 hours to avoid impaired drug absorption.
Antidiabetic drugs (insulin, sulfonylureas, metformin)
Preclinical data suggest marshmallow polysaccharides may modestly lower blood glucose; combined with hypoglycemic drugs this could theoretically produce additive glucose lowering.
Clinical note: Monitor blood glucose in diabetic patients using concentrated preparations; clinical relevance is likely small.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 6-15g | Daily | — | — | — |
Preparation Methods
Cold water macerate (cold infusion) of the root
Parts: Root
The preferred way to extract the mucilage. Steep about 2-4 g of chopped or powdered dried root in a cup of cold water for 1-2 hours (or overnight), stirring occasionally, then strain. Cold extraction preserves the heat-sensitive mucilage that hot decoction would degrade. Drunk to soothe dry cough, sore throat and gastric irritation. EMA lists the root as a traditional herbal medicinal product with well-established use for oral/pharyngeal irritation and associated dry cough.
Syrup or lozenges
Parts: Root
Aqueous root extract incorporated into a syrup or compressed lozenges, allowing the mucilage to coat and soothe the throat over a sustained period. Commonly used for symptomatic relief of irritative dry cough in adults and children.
Poultice / topical emollient
Parts: Root, Leaf
Powdered root moistened with warm water to form a soft, mucilaginous paste applied externally to inflamed skin, minor wounds, boils and insect bites as an emollient, soothing poultice.
Clinical Studies
Marshmallow Root Extract for the Treatment of Irritative Cough: Two Surveys on Users' View on Effectiveness and Tolerability
Two consumer surveys (822 users) of an aqueous marshmallow root extract taken as lozenges or syrup for dry, irritative cough over a 7-day treatment period. Both preparations were rated as effective for symptomatic relief of oral and pharyngeal irritation and associated dry cough, with a rapid onset of action and very good tolerability, consistent with the demulcent mechanism of the root mucilage.
Phytohustil and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve the migratory capacity of endothelial cells in vitro
Root extract of Althaea officinalis and the marshmallow-based product Phytohustil reduced pro-inflammatory mediators and oxidative stress in macrophages and improved endothelial cell migration in scratch-wound assays, providing a mechanistic basis (anti-inflammatory, anti-oxidative and epithelial-supportive activity) for the traditional use in irritated mucous membranes.
Historical Texts
De Materia Medica, Dioscorides
Roman era, 1st century CEThe Complete Herbal, Nicholas Culpeper
English Renaissance, 1653References
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). European Union herbal monograph on Althaea officinalis L., radix . European Medicines Agency (EMA/HMPC) (2016) [DOI]
- Fink C, Schmidt M, Kraft K. Marshmallow Root Extract for the Treatment of Irritative Cough: Two Surveys on Users' View on Effectiveness and Tolerability . Complementary Medicine Research (2018) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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