Hyaluronic acid(HA) is a straight chain macromolecularmucopolysaccharide composed Of repeat disaccharide units ofglucuronic acid and N-acetylglucosamine. It widely consists in theextracellular space of human and animal tissue, vitreum, umbilicalcord, skin joints synovia and cockscomb, etc. The commercial HA iscommonly a sodium salt, called sodium hyaluronate, habituallycalled hyaluronic acid. HA is a new biological at home and abroad.Its molecular weight is from several ten thousand to severalmillion. It''s aqueous solution has outstanding moisture keepingability, high viscoelasticity and lubricity. It is widely used incosmetics, pharmacy and health and beauty food.