Stool Color Changes (cont.)

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Yellow, greasy, and foul smelling stool

There are a variety of reasons why stool will be yellow and greasy appearing. It can be due to the intestine's inability to digest fat because of malabsorption such as in celiac disease and cystic fibrosis, or because the pancreas is unable to manufacture adequate digestive enzymes.

Yellow poop can be caused by gastrointestinal infection caused by giardiasis, a protozoan infection that can cause significant diarrhea.

Black tarry stools

Black stools are a worrisome symptom because it may be due to bleeding into the gastrointestinal tract, most often the esophagus, stomach or duodenum. Red blood cells are broken down by digestive enzymes and turn the stool black. These stools tend to be tarry and foul smelling. This can be a medical emergency; black tarry stools should not be ignored.

Blood from nosebleeds or from dental procedure and injuries can be swallowed and may be the cause of black stool.

Certain foods and medications can turn stool black, including iron, bismuth (Pepto Bismol, loperamide [Kaopectate]), beets, and licorice. While the stools may be black, they also tend to be gritty and not tarry.

Medically Reviewed by a Doctor on 9/30/2013

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