Background; To explore the efficacy of aspartate as NAD regenerating agent for ethanol and acetaldehyde oxidation, we performed crossover challenge in two groups of volunteers by coadministration of various doses of aspartate, asparagine and ethanol. Methods; 18 healthy male volunteers were randomly divided into two groups. 6 volunteers of the first group were administered 5 gm monosodium aspartate(MSA), 5 gm asparagine or placebo with 100 ml of 40˚ whiskey by the 3 way-crossover design, while 12 volunteers of the other group were administered placebo, 1, 2 or 5 bottles of Aspar^？？ containing 1 gm of MSA per bottle with 100 ml of 40˚ whiskey by the 4 way-crossover design. Ethanol(and acetaldehyde) concentrations in venous blood drawn at 0, 0.25, 0.5, 1, 2, 4, 8th hour after ethanol ingestion were analysed by gas chromatogaphy. Subjective symptoms, liver function tests and psychomotor function tests were also performed during the study periods. Result; Plasma concentration and AUC of acetaldehyde in asparagine and MSA trials on ethanol ingestion were significantly lower than those of placebo trial in the 1st group. Plasma ethanol concentration of 5 bottle Aspar^？？ trial was significantly lower than that of placebo trial in the 2nd group. Improvement of subjective symptoms or psychomotor performance by the treatment was not statistically significant. Conclusion; Aspartate and asparagine may be prospective candidates for acceleration of ethanol metabolism and prevention of ethanol toxicity.