Recently, halothane has been commonly used as an inhalation anesthetic agent, but it is generally accepted that it can cause postoperative hepatic dysfunction. Therefore, other anesthetic agents which have relatively less hepatotoxic effects have been recommended. This study was undertaken to evaluate the postoperative hepatic changes in patients with abnormal liver function or hepatobiliary diseases. Patients were divided into three subgroups hepatobiliary, other hepatobiliary and jaundice, or HBsAG(+) for the two anesthetic agents, enflurane and Thalamonal. Liver function tests were performed before surgery, and on the 3rd, 5th and 9th postoperative days. The results were as follows: 1) SGOT and SGPT showed a more statistically significant decrease in Thalamonal anesthesia than in enflurane anesthesia in hepatobiliary and jaundice or HBsAg(+) groups. However, in the other hepatobiliary groups, there were no significant differences between the anesthetics. 2) Total protein, albumin, total bilirubin, direct bilirubin and alkaline phosphatase levels were not shown to be significantly different between the use of the two anesthetics in all groups. It is suggested that postoperative hepatic changes may have improved more significantly in Thalamonal anesthesia than in enflurane anesthesia in hepatobiliary patients with abnormal liver function and jaundice or HBsAg(+) patients.