Stool examination: pictorial summary by Dr Frank Netter! A key point for lower gastrointestinal bleeding ! #SoMe4ColSurg #SoMe4Surgery @juliomayol @SWexner @MarkSoliman @DeliaCortesGuir @salo75 @pferrada1 @MISIRG1 @TecSurgeon @almagoch @BalibreaJose A change in the colour of one's stools may sometimes be due to dietary changes; though it could also reveal something about one's health. Where stool appears or , it 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, The Scoop On Poop Access Health Care Physicians