A composition that exerts an effect that increases serotonin in the brain through ingestion is provided. This agent for increasing serotonin in the brain contains epicatechin, which is obtained by steaming and drying camellia leaves to obtain dried camellia leaves, pouring an extract obtained by subjecting the dried camellia leaves thus obtained to distilled water or ethanol extraction on an ion exchange resin column, and then concentrating a 20% ethanol eluate to dryness.提供一種對於腦內血清素藉由經口攝取後發揮其增加作用之組成物。一種腦內血清素增加劑，其係含有經蒸煮茶花葉，進行乾燥而得到之乾燥茶花葉，將所得到之乾燥茶花葉用蒸餾水或乙醇萃取後之萃取物注入離子交換樹脂管柱中，經由20%乙醇洗出液經濃縮乾燥後所得到之表兒茶素。
