Gastrointestinal bleeding refers to any bleeding that originates in the gastrointestinal tract, from the mouth to the large bowel. The degree of gastrointestinal bleeding can range from nearly undetectable to acute, massive, life-threatening bleeding. Bleeding may originate from any site along the gastrointestinal tract, but is often divided into:

  • Upper Gastrointestinal Bleeding (considered any source located between the mouth and outflow tract of the stomach)
  • Lower Gastrointestinal Bleeding (considered any source located from the outflow tract of the stomach to the anus, small and large bowel included)

Gastrointestinal bleeding can range from microscopic bleeding, where the amount of blood is so small that it can only be detected by laboratory testing, to massive bleeding where pure blood is passed.

It is important to be aware of gastrointestinal bleeding, because it may herald many significant diseases and conditions. Prolonged microscopic gastrointestinal bleeding can lead to massive losses of iron and subsequent anemia. Acute, massive bleeding can lead to hypovolemia, shock, and even death.