Ancrod has been used in Europe for over 15 years for peripheral vascular disease, deep vein thrombosis, and central retinal venous thrombosis, and in patients at risk for thromboembolism. In a double-blind, randomized, placebo-controlled study at University Hospitals in Cincinnati, 20 acute cerebral infarction patients received a series of IV infusions of ancrod (ten) or placebo (ten) for seven days. Early fibrinolysis with a small decrease in fibrinogen was observed, and d-dimers were elevated at four hours, indicating early clot lysis. At three months, patients with moderate to severe strokes (less than 40 on the Scandinavian Stroke Scale) in the ancrod group showed average improvement by a factor of 3 over the placebo group. No bleeding, abnormal laboratory results, or deaths occurred, but ancrod was discontinued in one patient who had seizures. As a result of this study, a double-blind multicenter international clinical trial to further assess the safety and effectiveness of ancrod is being planned.