AS THE surgical approach to mesenteric vascular disease has become more sophisticated, the investigation of symptoms and signs of bowel ischemia, or even of unexplained abdominal pain, has become more complete. The mesenteric circulation may now be studied in man either selectively or by abdominal aortography; these examinations are now accepted diagnostic procedures in such problems. By the selective technique, an elegance of definition of the small branches is attained which aortography rarely affords (Fig 1); but in the presence of total luminal occlusion, the selective method is not applicable. Our experience with mesenteric vascular disease has emphasized both the difficulties in diagnosis and management, and the gratifying results of appropriate therapy. It is the purpose of this paper to indicate the role of collateral pathways in intestinal ischemia, some of the pitfalls in its recognition, and the potential for cure. I. The Role of Collateral Pathways in Intestinal Ischemia