The present invention pertains to a composition for improving intestinal barrier function, the composition containing a compound comprising a gallic acid residue as an active ingredient, the compound comprising a gallic acid residue being one or more substances selected from the group consisting of (A1) through (A3). (A1) A flavan-3-ol polymer comprising a galloyl group； (A2) a hydrolyzable tannin； (A3) one or more compounds selected from the group consisting of catechin gallate, epicatechin gallate, and gallocatechin gallate.本發明係關於一種腸道屏障功能改善用組成物，其含有具有沒食子酸殘基之化合物作為有效成分，且上述具有沒食子酸殘基之化合物，為選自由下述(A1)~(A3)所成之群的1種以上之化合物；(A1)具有沒食子醯基之黃烷-3-醇聚合物、(A2)水解性單寧、(A3)選自由兒茶素沒食子酸酯、表兒茶素沒食子酸酯及沒食子兒茶素沒食子酸酯所成之群的1種以上之化合物。
