Melena is the passage of black, tarry stools.
Hematochezia is the passage of red, bloody stools. Blood, as seen in the stool, can originate anywhere along the intestinal tract. A black stool usually means that the blood is coming from the upper part of the tract. Maroon-colored stools suggest that the blood is coming from the middle portion of the intestinal tract, and bright red from the large bowel or rectum. See also GI bleeding .