Bleeding in the gastrointestinal tract and colon cancer can cause black poop (also known as melena). But black stool doesn't always mean there is an underlying health concern. Dark-colored foods, iron ...

Stool changes with pancreatic cancer can include diarrhea, foul-smelling stool, constipation, and changes in stool color. The pancreas is an organ between the stomach and the spine that helps the body ...