Comfrey is a small, fast-growing herb with large, hairy leaves and small, bell-shaped flowers. It's been used for years by organic gardeners as a source of fertilizer, and by traditional herbalists to treat a variety of conditions. Historically it's been used to reduce the pain and swelling of sprained joints or broken bones.
In skin care, comfrey is valuable for the high quantities of allantoin in the plant. Allantoin is an anti-inflammatory and also stimulates skin cell turn over and collagen production.