Comfrey, also called bruisewort, knitbone and slippery root, is a member of the borage family that is native to Asia and Europe. Although this herb has a long history of use internally, it is no longer permitted in products sold in the U.S. or Europe that are intended to be ingested. The herb is still used to make salves, ointments and poultices for topical use because of the high degree of mucilage present in the leaf.