black tarry stool

I had a colonoscopy yesterday. later that day i ate oreo cookies. the next day had bowel movement i went to wipe it was black. can idea why

[vetty01]

Can my question be answered. what causes black tarry stool

[Morecambe]

I don't know whether oreo cookies have affected your motions.  However, the medical name for black tarry stools is MELENA (you can look it up on a google/yahoo posting etc).  Melena arises from intestinal bleeding (usually in the small intestine).

If you have melena you should seek prompt medical advice since rectal bleeding (whether "loose blood" or via melena) is never normal.

regards
Morecambe