The present invention provides an antiallergic agent which has no side effects, and which improves allergic diseases of infants, particularly newly born infants. The present invention is related to an antiallergic agent for infants which includes bifidobacteria.本發明提供一種改善乳兒、特別是出生後不久之乳兒之過敏性之疾病,且無副作用之抗過敏劑。本發明係關於一種含有雙歧桿菌之適合乳兒之抗過敏劑。