Problem to be solved: to provide a composition for treating inflammatory bowel disease (IBD) such as Crohn's disease and ulcerative colitis of mammals necessary for treatment.A composition for treatment or reduction of the inflammatory bowel disease of a mammal including a chemokine receptor CCR9 inhibitor, which is administered in combination with an anti TNF -. Alpha. Blocking antibody, and the chemokine receptor CCR9 inhibitor is a compound represented by the following formula, or its medicine Compositions that are readily acceptable salts or their N-oxides.Fig.4【課題】治療が必要な哺乳動物のクローン病や潰瘍性大腸炎などの炎症性腸疾患(IBD)を治療するための組成物の提供。【解決手段】ケモカイン受容体CCR9阻害剤を含む、哺乳動物の炎症性腸疾患の治療又は発症低減用組成物であって、前記組成物は、抗TNFα遮断抗体と併用投与され、前記ケモカイン受容体CCR9阻害剤は、以下の式で示される化合物、又はその医薬的に許容される塩、又はそれらのN-オキシドである、組成物。【選択図】図4C