The present invention addresses the problem of providing: a polyphenol stabilizer which, in processed goods which contain polyphenols such as cacao procyanidins or tea catechins, can minimize the epimerization of epicatechins or the decrease of procyanidins, the epimerization and the decrease occurring either during thermal extraction or heat sterilization or in storage under neutral or alkaline conditions； and a composition, food, drink, drug or cosmetic that contains the stabilizer. The stabilization of a polyphenol can be attained by making a stabilizer containing ellagic acid and/or punicalagin coexist with the polyphenol. The stabilizer may be a plant extract such as pomegranate extract, purified ellagic acid, purified punicalagin or a mixture of two or more of them.本發明之課題係於含有源自可可亞(cacao)之原花青素(procyanidin)類或源自茶之兒茶素(catechin)類等之多酚之加工製品中，抑制在熱萃取步驟、加熱殺菌步驟、及中性或鹼性條件下保存時產生之表(epi)體兒茶素類之差向異構化(epimerization)、或抑制原花青素類減低之多酚安定化劑，及提供含有該安定化劑之組成物、飲食品、醫藥品、化粧品。藉由使包含鞣花酸(ellagic acid)及安石榴苷(punicalagin)之至少一者之安定化劑與多酚共存，而可使多酚安定化。上述安定化劑可使用紅石榴萃取物等之植物萃取物、鞣花酸純化品、安石榴苷純化品及該等之混合物。
