What does it mean when you have black stool?

Could be blood: Black stool, especially if it has a tarry consistency, could be a sign of blood in the stool. Medications, such as pepto-bismol, can also turn stool black. Just to be sure, you should see your doctor to check for the presence of blood in the stool.

Oxidized Blood: Assuming you are not taking iron supplements, guzzling peptobismal, or munching on licorice sticks like they're going out of style, persistent black stools are an indication of a trickle bleed originating from the upper GI track like the stomach. You must get this checked by an endoscopist.

Black stools could: Be related to medicines/ vitamins such as peptobismol or iron. However, black, tarry, malodorous stools are like melena (gi bleeding). This would warrant medical evaluation.