Comfrey grows in Central Asia. The root is rich in allantoin, alkaloids and amino acids. Allantoin is a natural soothing, anti-irritant, and skin protectant that  increases the water content of the extracellular matrix which provides structural support to cells and is an important part of connective tissue. Allantoin also increases the smoothness of the skin; promotes cell replication; and promotes the healing of wounds, burns, and scars. Comfrey was well known in acient Greece where was used for regeneration of broken bones by soldiers of Alexander the Great.