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, 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, melanocyte vs melanosome vs melanin Melanotic refers to MELANIN not MELENA #medicine #doctor #humor #doctorsofinstagram #medreels #melanin Oral Melanotic Macule: Symptoms and Treatment Skinsight