The hepatotoxic effect on rats of long-term (55 weeks) administration of sake (a rice wine, 17% ethanol by volume) at large doses (average 12.6 g ethanol/kg body weight/day) was investigated in order to gain an insight into the reasons for the high incidence of liver fibrosis in Japanese alcoholics. Rats grew favorably under the experimental conditions, and daily variations in blood ethanol and acetaldehyde levels ranged from 3.8 to 21.1 mM and from O to 3.5 μM, respectively. Fatty and fibrotic liver was shown histologically and biochemically in sake-administered rats.