Patients diagnosed with pulmonary embolism (blood clot in the lung) or deep vein thrombosis (blood clot in a leg vein) are at risk for these blood clots to reoccur. Anticoagulant (blood-thinning) drugs are normally given immediately after the clot is discovered and are continued for a period of 3 or 6 months during which time the risk for recurrence is highest. Research has shown that when oral anticoagulants are used appropriately during this period, patients are less at risk for a recurrent blood clot and this risk reduction outweighs the potential for bleeding to occur.