What does your poop colour indicate? Pay attention. There's a lot to be learned by the colour and consistency of your stools, as well as the frequency and how easily passed Retroflexions.com The Rectal Bleeding Rainbow 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, Black or Tarry Stools UF Health Presence of melanotic stool in terminal ileum. Download Scientific Diagram