We describe a 37-year-old man with Churg-Strauss syndrome (CSS) and a uniquely diffuse anatomic distribution of gastrointestinal (GI) involvement. Eosinophilic infiltration of the jejunum with granulomatous and necrotizing vasculitis resulted in perforation with peritonitis. Inflammation of the sigmoid colon associated with ulceration was documented in combination with radiographic evidence of a gastric ulcer.Endoscopic biopsy and abdominal angiography were not diagnostic and might be of limited sensitivity in documenting GI vasculitis in patients with CSS. Abdominal involvement in CSS can lead to life-threatening ischemia and perforation of the GI tract. In such cases, surgical intervention may be necessary; as in this case, the addition of cyclophosphamide to systemic corticosteroid therapy may speed resolution and decrease mortality in CSS.