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 Melena: What Is It, Causes, Symptoms, Bleeding, Treatment, and More Osmosis Frontiers Review on melanosis coli and anthraquinone containing traditional Chinese herbs that cause melanosis coli MALENA: Melena is the medical term for black, tarry stools caused by the presence of digested blood. It typically indicates bleeding in the upper gastrointestinal (GI) tract, such as the: Stomach Duodenum