Category:Demulcents

A demulcent is a herbal medicine that soothes and protects inflamed or irritated mucous membranes by forming a viscous coating, typically through high mucilage content. The clinical use is principally in the gastrointestinal tract (gastritis, peptic ulcer, oesophagitis, reflux), in the upper respiratory tract (sore throat, dry cough, laryngitis), and in the urinary tract (cystitis, irritated urethral mucosa); topical demulcent application is used for inflammatory skin conditions and minor wounds.

The principal demulcent herbs share the chemistry of high-molecular-weight polysaccharides (mucilage), which dissolve or disperse in water to form a viscous gel. The mucilage coats the inflamed mucous surface and provides physical barrier and osmotic effect, with secondary reflex effects on inflammation through vagal afferents and through reduced contact between inflamed tissue and luminal contents. The action is mechanical and topical rather than systemic; the herbal preparation must reach the affected mucosa to act.

The foundational demulcents of Western use are slippery elm (Ulmus rubra, the Native American medicine adopted by the Eclectic tradition); marshmallow (Althaea officinalis; the root and leaf both used, the root higher in mucilage; the original "marsh-mallow" was a confection made from the boiled root); licorice (Glycyrrhiza glabra; cross-listed for sweetness and for the steroid-glycyrrhizin caveats); oats (Avena sativa; oat-straw decoction for demulcent baths in eczema, oatmeal porridge in gastric inflammation); plantain (Plantago major and P. lanceolata; cross-listed for vulnerary use); Iceland moss (Cetraria islandica; the cool-temperate respiratory demulcent); and Irish moss (Chondrus crispus; the seaweed-source carrageenan). The Ayurvedic licorice (yashtimadhu) and psyllium (Plantago ovata; both demulcent and bulk-forming) round out the principal set.

Slippery elm (Ulmus rubra), marshmallow (Althaea officinalis), licorice (Glycyrrhiza glabra), oats (Avena sativa), plantain (Plantago major), Iceland moss (Cetraria islandica), Irish moss (Chondrus crispus), psyllium (Plantago ovata), flaxseed (Linum usitatissimum; cross-listed for omega-3 and for bulk-fibre action), comfrey (Symphytum officinale; topical only because of pyrrolizidine alkaloids), corn silk (Zea mays; urinary demulcent), couch grass (Elymus repens), the Ayurvedic shatavari (Asparagus racemosus) for its mucilaginous root, and the rice and barley waters used as paediatric demulcents.

The boundary of this category is "herb whose principal action is mucilage-mediated protection of inflamed mucous membrane." The astringent-and-demulcent combinations (yarrow, agrimony, meadowsweet, raspberry leaf) where both actions co-exist are listed under astringents for their primary action with cross-reference here. The mineral demulcents (sucralfate, the bismuth compounds) are listed under mucosal protectants under anti-ulcer agents.

This category page is an encyclopedia article about its subject. The actual index of herbs belonging to the category is generated automatically by the wiki engine, from category-membership declarations on the individual herb pages, and appears at the foot of the page below the references.