Adult males and females of three strains of mice, C57BL/10J, C57BL/6J and DBA/2J, were intubated or injected intraperitoneally with 0.02 ml/g body weight of a 25% alcohol solution. Thirty minutes later, their blood alcohol levels (BAL) were measured. Another group of mice, including both sexes, representative of the three strains, was fasted for 12 h and sacrificed; their stomachs were removed, homogenized, and assayed for gastric alcohol dehydrogenase (GAD) activity. Higher BALs were found in all intubated females compared to the intubated males. The reverse was observed in the injected group, which showed the males with the highest BAL values. GAD activity was evidenced in both sexes of the three strains and it was highest in the males. Strain-related differences were evident in the intubated groups and not in the injected groups. Intubated DBA animals had the lowest BALs as well as the highest GAD values. The results provide evidence for first-pass alcohol metabolism in mice and show the effects of sex and strain on gastric oxidation of alcohol.