Provided is a composition which has high absorbability in vivo and excellent biological safety, and which can enhance the angiotensin-converting enzyme inhibitory activity induced by amino acids. The ratio in the composition of the total amount of an amino acid or a salt thereof and the total amount of a cyclic dipeptide or a salt thereof is set to a specific range. As a result, the angiotensin-converting enzyme inhibitory activity of the amino acid is enhanced.