PROBLEM TO BE SOLVED: To provide a medicine or a functional food capable of safely suppressing progress of diabetes mellitus or hypertension occupying the core of lifestyle-related diseases. SOLUTION: This medicine or functional food or suppressing rise of blood glucose level or blood pressure comprises a fruit polyphenol. The fruit polyphenol is derived from an immature fruit of apple, pear or peach belonging to the family Rosaceae. As a result, progress of diseases related to diabetes mellitus can be suppressed without accompanying an adverse effect.