Since Steven(1971) introduced the cardiovascular effects of isoflurane many characteristics of isoflurane were reported. Among many advantages of isoflurane its limited metabolism in the body results least effect on the liver. In order to compare the effects isoflurane and halothane on liver function in five each gynecologic patient with normal liver function test(LFT), we checked liver function preoperatively as control and postoperative 7th day as experiment. We also studied the effects of isoflurane on liver function in patients with abnormal LFT. The results were as follows: First, there were no difference on the effect of LFT between halothane and isoflurane in patient with preoperatively normal LFT. Second, inhalation of isoflurane in patient with abnormal LFT does not seem to worsen liver function furthermore.