Anticoagulation may exacerbate possible tendencies for an ischemic infarction to become hemorrhagic. Little is known of any potential added risk of aspirin plus anticoagulation for such hemorrhagic transformation. A patient is reported who sustained a cerebral infarction from carotid artery disease and was treated with aspirin. Anticoagulation was begun and aspirin discontinued when the patient experienced a transient ischemic attack. Despite good control of anticoagulation, the patient sustained a hemorrhage at the site of infarction. The prolonged effects of aspirin combined with anticoagulants may have potentiated the conversion of an ischemic to a hemorrhagic infarction. Caution is advised when using anticoagulation immediately following aspirin therapy in patients with cerebral infarction.