Let's talk about your bowels Four Seasons Dietetics The color of your stool: what does it say about your health? Insentials GASTROINTESTINAL HEMORRHAGE (2): Melena. Melena, the passage of black, tarry stools, usually implies blood loss greater than 500 ml originating anywhere between the oropharynx and the right hemicolon. Melena occurs most often, Dark Stools and Abdominal Pain: A Case Study of Mr. Arnold's Course Hero