The present invention relates to a pharmaceutical composition for preventing or treating inflammatory bowel diseases, which comprises 7,8-dimethoxy-4(5H),10-dioxo-1H-1,2,3-triazolo[4,5-c][1]benzo azepine, a prodrug thereof, preferably 2-(1-isopropoxycarbonyloxy-2-methylpropyl)-7,8-dimethoxy-4(5 H),10-dioxo-2H-1,2,3-triazolo[4,5-c][1]benzoazepine as a prodrug, or a pharmaceutically acceptable salt thereof. The pharmaceutical composition according to the present invention is effective in the prophylaxis and therapy of the inflammatory bowel diseases and has few side effects. Particularly, the pharmaceutical composition according to the present invention may exhibit strong prophylactic and therapeutic effects even on severe cases having resistance to the conventional therapeutics.
