This study was proposed to investigate the effects of water extract of aged black garlic on ethanol induced hangovers in rats. Male Sprague-Dawley rats weighing $180{pm}10;g$ were divided into the following three groups; control, 130 mg/kg, and 260 mg/kg of aged black garlic extract. Aged black garlic was administered orally 30 min before and 30 min after ingestion of 40% ethanol (5 g/kg, B.W.). The rats were killed 24 hr after ethanol treatment, and blood was taken from the caudal artery at 1, 3, and 5 hr to test for ethanol or acetaldehyde in the serum. Groups that were administered aged black garlic extract pre- and post-alcohol consumption showed a significant decrease in ethanol levels in the blood at 1, 3, and 5 hr. The acetaldehyde concentrations decreased in both 130 mg/kg and 260 mg/kg groups that were administered aged black garlic extract pre- and post-alcohol consumption. The activities of alcohol dehydrogenase seemed to be unaffected, although the aged black garlic showed slightly higher activities of acetaldehyde dehydrogenase in pre- or post-alcohol consumption. The aspartate aminotransferase (AST) activity in the serum, elevated by ethanol, was decreased by administering a high dosage of aged black garlic extract, but resulted in no significant change in serum alanine aminotransferase (ALT) activity. These results concluded that aged black garlic extract can reduce hangover syndrome through the elevation of ALDH.