Stool Color and Intestinal Bleeding

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Doctor's View on Stool Color and Intestinal Bleeding

Comment by John P. Cunha, DO, FACOEP

The normal color of stool is brown, which is due to a substance called bilirubin found in bile. When the color of your stool changes, it is often harmless and may be due to dietary choices. However, persistent changes in the color and smell of your stool could be caused by gastrointestinal (GI) bleeding. Sources of GI bleeding are reflected in the color and odor of the stool. 

  • Black stool: This is usually foul-smelling and is caused by upper intestinal bleeding (stomach or upper small intestine, ulcers, or tumors. It may also be caused when you take iron supplements or bismuth (Pepto Bismol).
  • Maroon or purple stool: This is caused by intestinal bleeding (usually in the small intestine or first part of the colon), ulcers, tumors, Crohn's disease, ulcerative colitis, or infections.
  • Bright red stool: This occurs when bright red blood gets mixed with or covers the stool as it passes through the rectum. This is caused by hemorrhoids, colon polyps, rectal fissures, massive gastrointestinal bleeding, or colon cancer.

Stool Color and Intestinal Bleeding Resources

Read patient comments on Stool Color Changes - Causes

Doctor written main article on Stool Color Changes

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