comfrey(redirected from Knitback)
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n. pl. com·freys
Any of various hairy perennial Eurasian herbs of the genus Symphytum, especially S. officinale, having variously colored flowers in coiled cymes and long used in herbal medicine.
A perennial herb, the leaves and roots of which contain allantoin, carotene, essential oil, glycosides, mucilage, resin, saponins, tannins, triterpenoids, vitamin B12 and zinc. Comfrey is a medicinal herb staple, promoting the growth of bone and connective tissue, and breaks down red blood cells (hence its popular name, bruisewort). It is anti-inflammatory, and has been used internally for haemorrhage, diarrhoea, gastric ulcers, colitis, bronchitis, whooping cough, and other respiratory tract infections; it is used topically for burns, bruises, sprains, boils, sore breasts, ulcers, gangrene, haemorrhoids and varicose veins.
Liver tumours may develop in lab rats when exposed to high levels; it is a potential carcinogen.