Marshmallow Root

Althaea officinalis has been used as a soothing agent for at least two millennia, and unlike much of traditional herbalism its mechanism is straightforward physical chemistry rather than pharmacology. The root contains large polysaccharide chains — mucilage — that swell in water into a viscous gel and form a protective film over inflamed epithelium. That film reduces mechanical irritation of cough receptors and gives damaged mucosa a barrier while it heals. The European Medicines Agency accepts marshmallow root as a traditional herbal medicine for oral and pharyngeal irritation with dry cough, and syrup and lozenge preparations have small clinical studies showing rapid symptomatic relief. Laboratory work has confirmed bioadhesion of the polysaccharide fraction to buccal tissue and shown it promotes epithelial cell viability. For gastritis and reflux the reasoning is the same but the evidence is largely traditional and preclinical. The practical caveats follow from the mechanism: the mucilage must physically contact the tissue, so syrups, lozenges and cold infusions outperform capsules for throat use, and because it coats the gut it can delay absorption of other medicines taken at the same time.