Anticoagulants are substances that interfere with normal blood clotting.
They are made by the body itself or created artificially by drug companies. Blood is an amazing substance. Blood clotting is the safety mechanism by which the body conserves its limited supply of blood when a blood vessel is opened and bleeding occurs. Anticoagulants are used to treat certain conditions that cause dangerous clots to form inside arteries and veins. The system that controls blood clotting is very complex.