L-Lactide or L-3,6-Dimethyl-1,4-dioxane-2,5-dione (FR-0638) is the optically active internal diester of L-lactic acid. Unlike the parent acid, L-lactide is an odorless solid. Frinton Laboratories, Inc. offers this in small to medium quantities, as a free-flowing crystalline powder, melting at about 98°C and with purity higher than 99%. This as well as the optically inactive DL-lactide are used in medical practice, after polymerization to polylactide, a biodegradable and bioactive thermoplastic aliphatic polyester, one of the largest consumed bioplastics in the world. It is often used as a protective layer in wound coatings, or as anchors, screws or mesh in surgery, since it degrades in about six months to the innocuous lactic acid.