Alpinia katsumadai is used in traditional oriental medicine as an antiemetic and for treatment of stomach disorders. This study was to investigate the effect of the 50% methanol extract of Alpinia katsumadai and Puerariae thunbergiana on ethanol metabolism in rat. The administration of 50% methanol extract of Alpinia katsumadai significantly decrease the ethanol concentration in rat. The AUC and Cmax of Alpinia katsumadai was 3.1 and 2.4 times less than the control group, respectively. It was more effective than Pueraria thunbergiana is known to as ethanol detoxicant. Furthermore, we tested on its ethanol metabolizing effect with the preparation containing this herb (Haeju pill) in beagle. The AUC of Haeju pill was about 1.9 times less than the control group. It was estimated that the extract of Alpinia katsumadai had feasibility as a ethanol detoxication agent.