A pharmaceutical composition for treating or relieving inflammatory bowel disease (IBD) is provided. The pharmaceutical composition includes an extract of Bupleurum as an active ingredient, in which the Bupleurum is selected from the group consisting of Bupleurum krylovianum, Bupleurum chinense, Bupleurum commelynoideum, Bupleurum scorzonerifolium, Bupleurum triradiatum, Bupleurum falcatum, Bupleurum kaoi and a combination thereof.