Definition
Gastrointestinal (GI) bleeding refers to any bleeding that starts in the gastrointestinal tract.
Bleeding may come from any site along the GI tract, but is often divided into:
Upper GI bleeding: The upper GI tract includes the esophagus (the tube from the mouth to the stomach), stomach, and first part of the small intestine.
Lower GI bleeding: The lower GI tract includes much of the small intestine, large intestine or bowels, rectum, and anus.