Comfrey (also "comphrey") is an important herb in organic gardening, having many medicinal and fertilizer uses. Contemporary herbalists view comfrey as an ambivalent and controversial herb that may offer therapeutic benefits but can cause liver toxicity.
One of the country names for comfrey was ‘knitbone’, a reminder of its traditional use in healing. Modern science confirms that comfrey can influence the course of bone ailments.
The herb contains allantoin, a cell proliferant that speeds up the natural replacement of body cells. Comfrey was used to treat a wide variety of ailments ranging from bronchial problems, broken bones, sprains, arthritis, gastric and varicose ulcers, severe burns, acne and other skin conditions. It was reputed to have bone and teeth building properties in children, and have value in treating "many female disorders". In past times comfrey baths were popular to repair the hymen and thus "restore virginity"[citation needed]. Constituents of comfrey also include mucilage, steroidal saponins, tannins, pyrrolizidine alkaloids, inulin, and proteins.