Churg-Strauss syndrome or allergic granulomatosis and angiitis is an uncommon systemic vasculitis chracteristized by asthma, hypereosinophilia, mono or polyneuropathy, non-fixed pulmonary infiltrates, paranasal sinus abnormality and extravascular eosinophil infiltration. Gastrointestinal manifestations occur in about 42% of patients. However, ulcer formation in gastrointestinal tract mucosa is a rare manifestation, usually discovered upon laparotomy or autopsy. We experienced a case of 40-year-old woman with Churg-Strauss syndrome, who presented multiple colonic ulcers on colonoscopy. She also had bronchial asthma, polyneuritis, peripheral blood eosinophilia and hemorrhagic bullous skin lesions with extravascular eosinophil infiltration. She improved with high dose corticosteroid and cyclophosphamide. We report this case with a review of the literature.