Symphytum officinale, also known as comfrey, is a perennial flowering plant native to Europe, growing in damp, grassy places. Comfrey was formerly used as an application to wounds and ulcers to stimulate healing, and was also given systemically for gastric ulceration and respiratory tract disease. In cosmetics and personal care products, Symphytum officinale leaf extract is used for its skin soothing and healing properties. The extract contains allantoin, a very gentle moisturizing ingredient. Allantoin is a keratolytic, which means it has the ability to smooth skin through exfoliation of the top layer of dead skin cells. Allantoin also has astringent properties. It is thought that the allantoin in Symphytum officinale leaf extract can accelerate healing and soothe inflamed or irritated skin. Although allantoin can be very beneficial to the skin, Symphytum officinale leaf extract also contains pyrrolizidine alkaloids that have the potential to aggravate the skin.