In the nature, Chitin widely exist in the cell walls of the lower plants and the shells of prawns, crabs and insects.

It is a linear high-molecular polysaccharide, i.e., natural neutral mucopolysaccharide. If it is treated with concentrated alkali to remove the acetyl, chitosan can be obtained. Chitin is chemically inert and does not react with body fluids. It does not involve in foreign body reaction with tissue, either. Additionally, it is non-toxic, anti-thrombotic, heat resisting and disinfectant. As alkaline polysaccharide, chitosan can remove acid, diminish inflammation reduce cholesterol as well as blood lipid.