Preventive effect of ginseng saponin fraction against ethanol intoxication of the liver of rats fed width 12% ethanol instead of water for 6 days was investigated. Control group was dosed 12% ethanol instead of water (free access) for 6 days and test group was dosed 0.1% ginseng saponin fraction in the 12% ethanol instead of water for 6 days. Normal rats was given only water freely. It was observed that the activities of alcohol dehydrogenase (ADH) and Microsomal ethanol oxidizing system (MEOS) of both control and test groups were higher than those of normal group while the activity of aldehyde dehydrogenate (ALDH) of control and test groups were lower than that of normal rats, However, the ALDH activity decrease of test group was much less than that of control groups. Electron micrograph showed that severely swollen and disrupted mitochondria and dilated and vesiculated ER can be seen in control group while dilated or vesiculated ER are very few and swollen or disrupted mitochondria can not be seen in test group. From the above experimental result, it seems that ginseng saponin might stimulate ethanol oxidation and the removal of acetaldehyde resulting in the decrease of ethanol intoxication of the liver,