PROBLEM TO BE SOLVED: To provide a palatable product blended with amino acid such as branched-chain amino acid as anti-fatigue material for exhibiting anti-fatigue function, of which degradation odor with time is effectively inhibited.SOLUTION: A degradation odor inhibiting agent for branched-chain amino acid includes imidazole dipeptide as active ingredient. Food and drink include the degradation odor inhibiting agent. A degradation odor inhibiting method for branched-chain amino acid includes imidazole dipeptide in an amount of 0.005 to 0.55 times the standard weight of branched-chain amino acid.