The problem of hepatotoxicity of clinically employed halogenated inhalation anesthetics has major implications for the practice of anesthesiology. Because of emerging disadvantages with all the available anesthetics, chemists continue to search for better compounds. In 1963 Terrel synthesized enflurane and many anesthesiologist used it, hoping to avoid the disadvantage of halothane. This study was undertaken to investigate the advantage of enflurane as compared to the disadvantege of halothane, by comparing of pre- and post- operative liver functions of 16 cases of halothane use and 16 cases of enflurane use. in this study, all cases physical status were all ASA class 1, and excluded patients who had any liver disease, jaundice, previous experience of halothane or enflurane anesthesis, and who had not been transfused during this study. The result of this study which compared pre-operative and post-operative liver function tests disclosed statistically significant change in SGOT(p<0.02). On table lll the comparison of liver function tests between halothane and enflurane disclosed significant difference and that enflurane in less hepatotoxic than halothane. Considering the allergic or the intermediate by-product theory of the mechanism of halethane hepatoxicity, it is desirable to avoid repeating the use of halothane in the near future. Thus, it seems to be safer to use enflurane instead of halothane.