Heparin is obtained from vertebrate liver, lung, mast cells, etc. Its function is unknown, but it is used in the form of a number of different salts to prevent blood clotting in and out of the body. As a glycosaminoglycan anticoagulant, sodium heparin binds to antithrombin III to form the heparin-antithrombin III complex.

　　Common heparin, low molecular heparin sodium and sulfonated reach liver decyl can prevent thrombosis, treatment of venous thromboembolism, unstable angina and myocardial infarction, ordinary heparin and low molecular heparin can also be used for hemodialysis in prevention of thrombosis, but diffuse intravascular coagulation (DIC) preferred common heparin, sodium sulfonated reach liver decyl preventing thrombosis cannot be used in hemodialysis.