To clarify the effects of alcohol consumption on hepatocellular injury, we examined aspartate and alanine aminotransferases (AST and ALT), and gamma-glutamyltransferase (GGT), together with weekly alcohol consumption calculated from a self-rating questionnaire, in 1113 Japanese salesmen. The thresholds of associations between alcohol consumption and liver markers were estimated by the benchmark dose (BMD) method. The AST, ALT and GGT were positively correlated with alcohol intake (p<0.001), as well as age and body mass index (BMI); the relations to alcohol were statistically significant even when controlling for age, BMI and smoking habit. Although the AST and GGT were associated with four types of alcoholic beverage (p<0.01), it was only whiskey that had close relation to the ALT (p<0.05). The thresholds of alcohol consumption (ethanol g/week), i.e., 95% lower confidence limits of the BMD, were 362 for AST, 660 for ALT, and 252 for GGT. The thresholds for GGT and AST in Japanese men seem to be somewhat higher than those reported in Western countries. It is suggested that hepatocellular injury (i.e., AST elevation) in Japanese men may emerge at the ethanol level of more than 50 g/day.