Causes of Black Tarry Stool
False Melena: False melena is black tarry stool caused by food, supplements, medications, or minerals. Iron supplements can trigger false melena, along with foods that are blue, black, or green in color. Some examples of factors that can trigger false melena include black licorice, blueberries, iron supplements, lead, and bismuth.
Melena: This is a result of upper gastrointestinal bleeding in the esophagus, stomach, or small intestine. Other causes of melena include bleeding ulcer, gastritis, esophageal varices, or a Mallory-Weiss tear – this is a tear of the mucous membrane that connects the esophagus and stomach.
Hematochezia: This is the passage of black tarry stool when bleeding is present in parts of the lower digestive tract, such as the colon, rectum, or anus.
Diet: Certain foods can cause stool to appear black or tarry. These foods include black licorice, blueberries, dark chocolate cookies, red-colored gelatin, beets, and red fruit punch.
Medications and Supplements: Common over-the-counter medications to treat the digestive system or diarrhea which contain bismuth can cause stool to appear black. Iron supplements are another common cause of black stool.
Other Causes: Other causes of maroon or black-colored stool are anal fissures, diverticulosis, hemorrhoids, inflammatory bowel disease, infection of the intestines, and trauma or foreign bodies.
Signs and Symptoms of Black Poop
Signs and symptoms of black poop often relate to its underlying cause. Here is a list of potential signs and symptoms that may accompany black tarry poop:
- Abdominal pain and cramping
- Bloating or abdominal swelling
- Changes in bowel habits
- Diarrhea
- Gas or indigestion
- Flu-like symptoms
- Foul-smelling stool
- Nausea and vomiting
- Poor appetite
- Rectal pain and burning sensation
- Unexpected weight loss
Diagnosing Black Stool
To properly diagnose the underlying cause of your black tarry stool, your doctor will do a complete medical examination. They will run blood tests and imaging scans to determine any infection, blockages, or anything else that can contribute to black tarry stool.
A colonoscopy or endoscopy may also be recommended to have a better look at the stomach and colon to check for any tears, polyps, or other sources of bleeding.
Treating Black Stool
Treatment for black tarry stool depends on the underlying cause. Some possible treatments for black tarry stool include antibiotics to combat infections, acid-reducing medications to treat ulcers, surgery for abnormal veins, removal of polyps, or simple diet changes like avoiding foods which can cause the stool to appear black or tarry.
How to Prevent Black Stool
If black tarry stool is caused by your diet, you may wish avoid foods that are blue, black, or green in color. You will also want to increase your fiber intake to reduce tears in the colon. Ingest more raspberries, pears, whole grains, beans, and artichokes.
For some conditions, a high-fiber diet is not recommended. Your doctor will help you find the best way to eat based on your unique needs.
Related: Floating poop (steatorrhea): Understand why your stool floats