The most widely used coumarin anticoagulant in clinical practice is warfarin, also known as benzylacetone coumarin. In addition, there are dual coumarins, vinblastine coumarin, vinblastine coumarin is also called new anticoagulation. Warfarin is a kind of vitamin K antagonist, this kind of drugs in the process of taking should pay attention to regular monitoring INR, that is, international normalized ratio, this kind of anticoagulant in the process of application, some people may have brain hemorrhage, must pay attention to monitoring INR. the indications of this drug, such as can be applied to pulmonary embolism, atrial fibrillation before and after the resuscitation of treatment, for mechanical prosthetic valve replacement after the People need long-term oral warfarin.