Blood transfusion can adversely affect patient outcome and graft survival in orthotopic liver transplantation (OLT). With this respect, prophylactic aprotinin administration decreases blood loss, transfusion requirements, and the hemodynamic changes associated with graft reperfusion in patients undergoing OLT. However, data indicate limiting the use of aprotinin in OLT: (a) clinical, biological, echocardiographic, and postmortem findings recorded in patients with chronic liver disease or undergoing OLT suggest that a continuous prothrombotic state exists in these patients. Whether the inhibition of fibrinolysis associated with aprotinin therapy will expose some patients to untoward thrombosis is questionable; (b) aprotinin does not appear to alter postoperative outcome in patients undergoing OLT; (c) aprotinin decreases blood transfusion requirements only when surgery is associated with significant blood loss. However, at the present time, median transfusion requirements of 2 to 5 red blood cell units are required in OLT.