Rectal wall bleeding--an overlooked source of massive lower gastrointestinal hemorrhage

Two cases of acute massive bleeding from the rectum are described. In both cases, the diagnosis was made angiographically. Some points of angiographic technique are discussed. In both cases, there had been previous negative sigmoidoscopy. Care must be taken to include the entire rectum on the films obtained during injection of the inferior mesenteric artery regardless of findings on sigmoidoscopy.