It has been reported that the stomach is a source of leptin, which is the product of the obese (ob) gene. In the present study, the effect of alcohol on leptin level in serum, gastric mucosa, and adipose tissue was studied to understand the relationship between appetite and alcohol consumption. Male Sprague-Dawley rats were administered 1 ml of 25% ethanol perorally. Leptin levels in the serum, gastric mucosa, and adipose tissue were measured. The serum leptin level was significantly decreased 3 and 6 hr after ethanol administration, although the gastric leptin level was not affected. The leptin level in the adipose tissue was significantly increased 3 hr after administration. We conclude that the decreased serum leptin level after ethanol administration might be due to suppression of leptin secretion from adipose tissue to the systemic circulation. These findings might be important for understanding the relationship between alcohol consumption and appetite.