摘要Interferon (IFN) is a multifaceted immunomodulator that is effective against many diseases,including chronic hepatitis B and chronic hepatitis C infection.IFN defends against viral infection,but may also cause various side effects,such as ulcerative colitis (UC).Herein,we present a case of UC triggered by pegylated interferon alpha-2b (PEG-IFN-α-2b) therapy in a patient with concurrent chronic hepatitis B(CHB) infection.The diagnosis was based on typical clinical symptoms,colonoscopy findings,colonic mucosal biopsy,and histopathology.Accordingly,treatment with mesalazine was initiated without stopping PEG-IFN-α-2b.Fortunately,UC relieved gradually without compromising the effects of treat-ment.Simultaneously,we conducted a literature review of previously published case reports on the side effect of UC in patients with underlying chronic hepatitis.Various reactions have been reported,including induction,exacerbation,and no change.This is the first report of UC triggered by PEG-IFN-α-2b in a CHB patient.We recommend that physicians pay attention to the rare side effect of UC during administration of PEG-IFN-α-2b.Mesalazine can relieve UC with sustained use of PEG-IFN-α-2b.