Thrombosis is the formation of clot and is one of the most common disorders of coagulation. This can occur in cases of atrial fibrillation (AF) and cause a stroke or can occur in the deep veins and cause a pulmonary embolism (PE). These are very serious conditions leading to both disability and death. Prevention of these disorders is one of the very important considerations in medical management. The predispositions for thrombosis include mainly atrial fibrillations and immobility. Traditionally we have two classes of anticoagulants that are commonly used.