Comfrey (Symphytum officinale), also known as Common Comfrey, Blackwort, Bruisewort, Knitbone, Slippery root, and Gum plant (among others), is a perennial herb of the family Boraginaceae. It is native to Europe, growing in damp grassy places on the banks of rivers and ditches. In the Middle Ages, Comfrey was not only a well-known remedy for broken bones but was used to treat a wide variety of ailments, from arthritis and bronichial problems to gastric ulcers and wound-healing. One of the constituents in Comfrey is allantoin which stimulates cell proliferation and thereby accelerates wound-healing, both internally and externally.
Comfrey Medical Uses
Medicinally used are the root and leaves of Comfrey. Besides allantoin, they also contain mucilage, tanning, steroidal saponins, Vitamin B12, pyrrolizidine alkaloids, asparagine, inulin, resin, gum, and starch. Allantoin can not only prevent scar formation in superficial wounds, it is also able to diffuse through skin and tissue, which is why Comfrey was traditionally used as an external application for the treatment of bone fractures. But it also helps treat sprains, arthritis, varicose and gastric ulcers, and a wide variety of skin conditions. In the past, it was popular to take Comfrey baths before marriage, as it was believed that this restored virginity. Comfrey also contains hepatoxic pyrrolizidine alkaloids which can lead to liver failure when taken in high doses. Therefore, it is not advised to use Comfrey internally.
Comfrey Dosage and Risks
Comfrey products are made from the leaves or the roots. Some advise not to use root preparation, as they are more likely to cause poisening. There are Comfrey ointments, Comfrey creams, Comfrey poultices, and Comfrey liniments available on the market. Comfrey preparations are applied to the skin to relieve pain from fractures, sprains, or pulled muscles, but also to treat minor wounds and skin conditions. It is advised to use only the amount recommended on the label and to never use more than that. Comfrey products shouldn’t be used for more than 4 to 6 weeks within a year. To use Comfrey on dirty or deep wounds should be avoided as the rapid healing properties of the allantoins may then trap dirt or pus and lead to abscesses. Pregnant or nursing women should not use Comfrey products at all. There are no reports of harmful drug interactions.