A composition containing a peptide and an electrolyte excretion promoter, which comprises a peptide or a peptide mixture which is obtained by lysing a food-origin protein with a protease and has an activity of inhibiting angiotensin converting enzyme, and one or more electrolyte excretion promoters selected from chitosan, alginic acid or a salt thereof, and further relates to a food containing the same. Said composition has excellent inhibitory activity to rise of blood pressure by synergistic effects of both components.