Comfrey
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.