Disclosed is a composition which can be used for the treatment or prevention of a cerebral nerve disease and the improvement in a cerebral function, has few adverse side effects, and is highly safe even when the composition is administered for a long period. The composition comprises an astringent skin of a peanut and/or an extract of the astringent skin as an active ingredient, and can be used for at least one use application selected from the group consisting of the treatment of a cerebral nerve disease, the prevention of a cerebral nerve disease and the improvement in a cerebral function. The cerebral nerve disease may be at least one member selected from the group consisting of a depression condition, an anxiety condition and a memory disorder. The improvement in a cerebral function may be the improvement in a memorizing/learning ability. The composition can be prepared into any one selected from a food, a food additive, a pharmaceutical product, a feed and a pet food.
