Clay-Colored Stools | What Causes Clay-Colored Stools?

Black stools

In most cases, it is because you’re using a medicine that darkens the color of the stools. Blueberries, black licorice, and iron supplements are common causes of dark stools. However, if a very foul odor accompanies black stools, it is maybe due to bleeding in the upper portion of the gastrointestinal tube.