The present study was undertaken in order to elucidate the effect of ginseng butanol fraction on ethanol induced hepatic aniline hydroxylase activity in rat. Ginseng butanol fraction increased the hepatic aniline hydroxylase activity which is inhibited by ethanol addition in the enzyme assay system, whereas not shown the ginseng effect in ethanol absence condition in vitro. It was found that ginseng butanol fraction improved the affinity of aniline hydroxylase under presence of ethanol in the reaction mixture. On the contrary ginseng butanol fraction showed significant decreasing effect on aniline hydroxylase activity induced by ethanol administration. These results suggest that ginseng butanol fraction regulate the hepatic aniline hydroxylase activity which is induced by ethanol consumption.