Conventional (Conv; n=8–15) and germ-free C57BL/6 mice (GF; n=8–16) were gavaged with ethanol (300μl, 30% vol/vol) or an isocaloric amount of dextrose (300μl, 0.42 g/ml) once, and harvested after 9 h. Expression levels of indicated ethanol-metabolizing genes were determined in stomach, proximal, mid and distal small intestine, cecum, proximal and distal colon. Hepatic expression in conventional mice is shown as comparison. *p<0.05.