Coumadin-induced gastrointestinal hemorrhage associated with an ileal duplication. A 31-year-old man had recurrent gastrointestinal hemorrhage after aortic valve replacement and initiation of anticoagulation therapy with coumadin. Radionuclide bleeding scan and subsequent contrast angiogram demonstrated a site of hemorrhage in the distal ileum, and at surgery a 1.8-cm spherical duplication was found. On histologic examination, the duplication was lined with normal ileal mucosa, and near the mouth of the duplication an inflammatory ulceration proved to be the site of hemorrhage. In a young patient with anticoagulation-associated gastrointestinal hemorrhage, alimentary tract duplication should be considered. 