We evaluated the effects of prostaglandin E1 (PGE1) on the liver function and hemorrhage after total hip arthroplasty (THA). Twenty patients with normal liver function were randomly divided into two groups. The patients were anesthetized with spinal anesthesia using 0.5% bupivacaine 4 ml and epidural anesthesia. The laryngeal mask was inserted after administrations of 1.5-2 mg.kg-1 of propofol and 0.8 mg.kg-1 of succinylcholine. PGE1 was infused in the PGE1 group at a rate of 0.01 microgram.kg-1.min-1 (PGE1 group) during and after the operation (30-40 hrs). GOT and GPT values were evaluated before, and at the end of operation, and on 1, 4 and 7 postoperative days in each group. The amount of hemorrhage was measured at the end of operation and on 1, 2, 3 and 4 postoperative days in each group. GOT values on 1 and 4 postoperative days in PGE1 group were significantly lower than those in the control group. GPT values on 1, 4 and 7 postoperative days in PGE1 group were also significantly lower than those in the control group. The amount of bleeding during the operation and postoperative hemorrhage did not differ significantly between the two groups. These results suggest that PGE1 may prevent postoperative liver damage, but it may not affect the amount of postoperative bleeding.