Heparin injection is an anticoagulant. It is used to decrease the clotting ability of the blood and help prevent harmful clots from forming in blood vessels. This medicine is sometimes called a blood thinner, although it does not actually thin the blood. Heparin will not dissolve blood clots that have already formed, but it may prevent the clots from becoming larger and causing more serious problems.

　　Heparin is used to prevent or treat certain blood vessel, heart, and lung conditions. Heparin is also used to prevent blood clotting during open-heart surgery, bypass surgery, kidney dialysis, and blood transfusions. It is used in low doses to prevent the formation of blood clots in certain patients, especially those who must have certain types of surgery or who must remain in bed for a long time. Heparin may also be used to diagnose and treat a serious blood condition called disseminated intravascular coagulation.