Black Stool

About

Black or tarry stools with a foul smell are a sign of a problem in the upper digestive tract..

Eating black licorice, blueberries, blood sausage, or taking iron pills, activated charcoal, or bismuth medicines like Pepto-Bismol, can also cause black stools. Beets and foods with red coloring can sometimes make stools appear reddish. In all these cases, your doctor can test the stool with a chemical to rule out the presence of blood.

Bleeding in the esophagus or stomach (such as with peptic ulcer disease) can also cause you to vomit blood.

Causes

The color of the blood in the stools can indicate the source of bleeding.

• Black or tarry stools may be due to bleeding in the upper part of the GI (gastrointestinal) tract, such as the esophagus, stomach, or the first part of the small intestine. In this case, blood is darker because it gets digested on its way through the GI tract.
• Red or fresh blood in the stools (rectal bleeding), is a sign of bleeding from the lower GI tract (rectum and anus).

Peptic ulcers are the most common cause of acute upper GI bleeding. Black and tarry stools may also occur due to:

• Abnormal blood vessels
• A tear in the esophagus from violent vomiting (Mallory-Weiss tear)
• Blood supply being cut off to part of the intestines
• Inflammation of the stomach lining (gastritis)
• Trauma or foreign body
• Widened, overgrown veins (called varices) in the esophagus and stomach, commonly caused by liver cirrhosis
• Cancer of the esophagus, stomach, or duodenum or ampulla

When to Contact a Medical Professional

Call your health care provider right away if:

• You notice blood or changes in the color of your stool
• You vomit blood
• You feel dizziness or lightheadedness

In children, a small amount of blood in the stool is most often not serious. The most common cause is constipation. You should still tell your child's provider if you notice this problem.

Alternative Names

Stools - bloody; Melena; Stools - black or tarry; Upper gastrointestinal bleeding of the blood back to the person.