Russian comfrey (Symphytum x uplandicum) has a long history as a curative and a garden booster. Native to the riverbanks of Europe, the plant is now found in North America and western Asia. It bears broad, hairy leaves and small bell-like flowers in cream or purple; the turnip-like root is black. Comfrey, once known as boneset, was used to treat broken bones, sprains, strains, and arthritis as well as for bronchial problems, gastric distress, and varicose ulcers. The herb contains allantoin, believed to stimulate skin-cell growth and reduce inflammation. comfrey should only be used topically as a salve or poultice, or as an essential oil.