A 35-year-old man with anti-HCV-antibody positive chronic hepatitis was treated with interferon (IFN) ‐α2b from December 27, 1999. On February 4, he complained of lower abdominal pain and melena, and was admitted as an emergency. Total colonoscopy revealed mucosal edema and erosions in the descending colon. The biopsied specimen showed interstitial edema with infiltration of inflammatory cells. IFN treatment was discontinued and patient was conservatively followed up. Colonoscopy performed 10 days after admission revealed improvement of erosions and mucosal edema. He had no past history of diabetes mellitus, hyperlipemia, or heart disease. Thus it appeared that ischemic colitis was associated with the IFN treatment. The mechanisms of ischemic colitis is thought to be related to an autoimmune phenomenon by IFN. Other mechanisms may be caused by cytokines associated with IFN. Only nine cases of ischemic colitis during IFN treatment had been reported. We reported a rare case of ischemic colitis complicated with IFN treatment.
