Provided is a composition which has high bioabsorbability and excellent biological safety and can enhance an angiotensin-converting enzyme-inhibiting activity ascribable to an amino acid. The ratio of the total amount of an amino acid or a salt thereof to the total amount of a cyclic dipeptide or a salt thereof in the composition is set to within a specific range. This enhances the angiotensin-converting enzyme-inhibiting activity brought about by the amino acid.
