Agents that prevent the blood from clotting.
Anticoagulants are medicinal substances that prevent or stop the clotting of blood. Heparin, a naturally occurring anticoagulant extracted from animal tissues, works to stop the coagulation of blood by preventing the formation of prothrombin, fibrin and thrombin. Anticoagulants are often used to treat bedridden patients who are at risk of developin...
drugs used to stop abnormal blood clotting, such as to prevent stroke 
Drugs that reduce the ability of the blood to clot. Also called blood thinners.