To consider the pathogenesis of ethanol-induoed fatty liver from the aspect of the drug-metabolizing system, the amount of cytochrome P-450 and lipid peroxides was measured in the liver tissues of the rats given the ethanol diet mixed with Pantethine (antioxidant). After fed the ethanol diet only for 8 weeks, the rats were fed the ethanol diet mixed with Pantethine for 4 weeks. The rats were divided into 3 groups according to diet as follows