To provide a naturally originated hypotensive action-having medicine or food composition which is safe and little requires worries against side effects and the like, even when administered for a long period.

This hypotensive action-having composition is characterized by containing silk protein obtained by removing sericin forming the outer layer portion of silk from the silk, especially a fibroin hydrolysate capable of being well absorbed in the bodies. The hypotensive action-having composition, food or medicine preferably further contains mulberry leaves, especially mulberry leaf powder, mulberry leaf extract and mulberry leaf extract powder, in an amount of 0.5 to 50 pts. wt. (converted into the original galenical) per pt. wt. of the silk protein.