To provide a tripeptide with reduced adverse effect and an excellent neurocyte activating effect, and to provide a food, a cosmetic and an anti-dementia agent comprising the same.

The neurocyte activating tripeptide has a structure represented by X-Tyr-Phe, wherein X is an amino acid selected from Leu, Phe, Pro, and Gln, and especially, Leu-Tyr-Phe or Phe-Tyr-Phe. The tripeptides are obtained by heating pulverized product of nerves collected from squids body belonging to Dibranchia Decapodiformes, with proteases. The food preparation comprises the tripeptide with neurocyte activating effect, chlorogenic acid and chlorogenic acid esterase. The cosmetic comprises the tripeptide with neurocyte activating effect, ferulic acid and chlorogenic acid esterase. The anti-dementia agent comprises the tripeptide with neurocyte activating effect as a principal component.