We experienced a case of drug-induced hypersensitivity syndrome (DIHS) for salazosulfapyridine (SASP). After we started administration of SASP in a 26-year old man with ulcerative colitis (UC), he had symptoms resembling infectious mononucleosis, high fever, skin eruption, cervical lymphadenopathy, elevate white blood cell count with atypical lymphocyte, and liver dysfunction. We diagnosed the illness as drug-induced hypersensitivity syndrome (DIHS) due to SASP. We halted SASP and started administration of methylprednisolone and prednisolone but his condition deteriorated. We changed to administration of betamethasone and he recovered. In cases of DIHS accompanied by UC, we should administer drugs carefully and recognize serious complications.