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, Melena: What Is It, Causes, Symptoms, Bleeding, Treatment, and More Osmosis Stool Colors and What They Can Tell You Your stool color can carry important clues about digestion, diet, or even disease. Most shades are harmless, but some changes signal the need for There are no 50 shades of melena, only one color: Black; and it's a color that smells bad. Otherwise it's not melena or it's derivatives (melenic, melanotic, melenatonic ) Great thread w a