PROBLEM TO BE SOLVED: To provide an intestinal barrier function improver which can be taken safely.SOLUTION: Lactulose is used as an active ingredient of an agent for treatment and/or prevention of disease associated with the failure of an intestinal barrier function, such as inflammatory bowel disease.COPYRIGHT: (C)2015,JPO&INPIT【課題】安全に摂取できる腸管バリア機能改善剤を提供すること。【解決手段】ラクチュロースを、炎症性腸疾患のような腸管バリア機能の破綻に関連する疾患の治療用及び/又は予防用の薬剤の有効成分とする。【選択図】図1