Introduction Early recognition of situations where compromise of the blood supply to the intestine is present is much to be desired. Coexisting intestinal obstruction makes early diagnosis even more imperative. One of the most frequently used diagnostic aids, the x-ray of the abdomen, has been found to be generally unreliable in this condition.1,2 An interesting finding in several large series of cases was that an average of 35% of the cases of severe strangulation obstruction never presented gas and fluid levels characteristic of an intestinal obstruction.3 Early investigations led us to feel that strangulation must produce a diminution of gas and fluid transport which might be utilized in the differentiation of simple from strangulation obstruction. Vest4 administered oral sodium diatrizoate (Hypaque) to a small series of dogs and concluded that failure of passage of the material from the stomach and duodenum occurred with strangulation obstruction. It is