Black or tarry stools with a foul smell are a sign of a problem in the upper digestive tract. It most often indicates that there is bleeding in the stomach, small intestine, or right side of the colon.
The term melena is used to describe this finding.
Alternative Names
Stools - bloody; Melena; Stools - black or tarry; Upper gastrointestinal bleeding; Melenic stools
Considerations
Eating black licorice, blueberries, blood sausage or taking iron pills, activated charcoal, or medicines that contain bismuth (such as 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 in the esophagus, stomach, or duodenum
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.
What to Expect at Your Office Visit
Your provider will take a medical history and perform a physical exam. The exam will focus on your abdomen.
You may be asked the following questions:
Are you taking blood thinners, such as aspirin, warfarin, Eliquis, Pradaxa, Xarelto, or clopidogrel, or similar medicines? Are you taking an NSAID, such as ibuprofen or naproxen?
Have you had any trauma or swallowed a foreign object accidentally?
Have you eaten black licorice, lead, Pepto-Bismol, or blueberries?
Have you had more than one episode of blood in your stool? Is every stool this way?
Tests for the presence of Helicobacter pylori infection
Capsule endoscopy (a pill with a built in camera that takes a video of the small intestine)
Double balloon enteroscopy (a scope that can reach the parts of the small intestine that are not able to be reached with EGD or colonoscopy)
Severe cases of bleeding that cause excessive blood loss and a drop in blood pressure may require surgery or hospitalization.
References
Chaptini L, Peikin S. Gastrointestinal bleeding. In: Parrillo JE, Dellinger RP, eds. Critical Care Medicine: Principles of Diagnosis and Management in the Adult. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 72.
Savides TJ, Jensen DM. Gastrointestinal bleeding. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 20.
Review Date:
5/4/2022
Reviewed By:
Michael M. Phillips, MD, Emeritus Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
