The problem to be solved by the present invention is to provide an opioid peptide degrading agent or a composition for degrading opioid peptides, which has no restriction on dietary habits, has no side effects even when used on a daily basis, and can be continuously used with peace of mind. The subject is a bacterium belonging to the genus Bifidobacterium, a culture of the bacterium, and / or a treated product of bacterial cells of the bacterium as an active ingredient, and an opioid peptide decomposing agent or a composition for decomposing an opioid peptide, and a drug for decomposing an opioid peptide. The problem is solved by a composition or a food / beverage composition for degrading opioid peptides.本発明が解決しようとする課題は、食生活の制限がなく、日常的に利用しても副作用のない、安心して継続利用できるオピオイドペプチド分解剤又はオピオイドペプチド分解用組成物の提供である。該課題を、ビフィドバクテリウム属細菌、前記細菌の培養物、及び／又は前記細菌の菌体処理物を有効成分とする、オピオイドペプチド分解剤若しくはオピオイドペプチド分解用組成物、オピオイドペプチド分解用医薬組成物又はオピオイドペプチド分解用飲食品組成物で解決する。
