Gastrointestinal bleeding can present in several ways, including black stools, vomiting blood, maroon stools, rectal bleeding, or iron deficiency anemia discovered on routine laboratory testing. In some cases, bleeding develops slowly over time, while other patients experience more sudden or severe symptoms.

Potential causes range from ulcers and gastritis to diverticular disease, inflammatory bowel disease, hemorrhoids, esophageal varices, polyps, or gastrointestinal cancers. Endoscopic evaluation plays an important role not only in diagnosis, but also in treating many causes of bleeding without the need for surgery.