Corn peptide without free amino acids produced by the hydrolysis of original proteinase and purification processes was composed of various oligopeptide fractions. Corn peptide was comparatively rich in the branched chain amino acids (BCAA) and alanine. The acute toxicity of acetaldehyde was suppressed by the prior administration or i.p. injection of corn peptide in mice. Also, the serum ethanol and acetaldehyde concentration was significantly decreased by the prior or simultaneous administration of corn peptide in SHRSP rats after a dose of ethanol. It is expected that the hangover syndrome of alcohol is reduced by the prior administration of corn peptide and the alcoholic liver disordered is prevented with keeping on the administration of corn peptide.