What are the causes of dark stools?
Treatment of black stools depends on the underlying cause.

Dark stools could be due to minor causes, such as dietary changes, or medications, such as iron supplements. However, some underlying conditions, such as intestinal bleeding, may result in dark brown or black stools.

What are the causes of dark stools?

Foods that cause dark-colored stools

Foods that cause dark-colored stools include:

The color of the stools after taking these foods is generally dark brown, bluish, reddish, and black. The stool color should change to the usual when you stop taking those foods.

Medications that result in dark-colored stools

  • Iron supplements
  • Antidiarrhea medications, containing bismuth subsalicylate

Dark brown stools could be sometimes because of bleeding in the digestive tract. The color and quality of the poop usually depend on the site of bleeding and the movement of stool through the digestive tract.

  • The black color stools with sticky consistency are due to the bleeding in the esophagus, stomach, and small intestine.
  • Bright red stools are due to bleeding in the lower digestive tract, especially from the colon and the anus.
  • Red stripping over the stool is due to the hemorrhoids in the digestive system's exit.

When dark brown stools are due to bleeding in the digestive tract and factors, such as medications and foods, are ruled out, immediate medical care should be sought.

What digestive conditions cause dark stools?

Dark stools may occur due to:

Here are some serious causes of dark stools, which should not be ignored and need medical attention.

Bleeding ulcer

Bleeding or a wound on the inner lining of the stomach or intestine. When the blood is exposed to gastric acids, that turn stools black and sticky. This is called melena. It is a sign of upper gastrointestinal bleeding.

Alcohol consumption and excess intake of nonsteroidal anti-inflammatory drugs result in gastrointestinal bleeding.

Other signs of intestinal bleeding are:

Esophageal and gastric cancers

Any benign or malignant tumor on the gastrointestinal lining results in the rupture of the intestinal lining and leads to bleeding. The blood gets combined with gastric juices and causes dark and sticky stools.

Other symptoms of esophageal cancers include:

Other symptoms of gastric ulcers:

Esophageal tearing

Severe coughing results in esophageal tearing called Mallory-Weiss tear, resulting in bleeding.

Other symptoms of Mallory-Weiss tear include:

Esophageal varices

The swollen veins in the esophagus are called esophageal varices. These varices break open and lead to bleeding, which causes dark stools. These abnormal veins are most seen in people with liver diseases.

Other symptoms of esophageal varices:

Other life-threatening causes of dark stools

QUESTION

Pancreatitis is inflammation of an organ in the abdomen called the pancreas. See Answer

How is the cause of black stools diagnosed?

If the symptoms are severe, visit a doctor immediately. They may ask you about the signs and history of the condition. Then, your doctor may do a physical examination and order several blood and stool tests.

A few diagnostic imaging, such as colonoscopy or gastroscopy, are done to check the condition of your digestive tract.

  • Colonoscopy is done under sedation, and your doctor will insert a flexible tube into the anus with a camera attached to see the inside of the colon and look for the cause of symptoms.
  • Gastroscopy is like a colonoscopy, but the flexible thin tube is inserted through the throat with a camera attached to it. It helps identify lumen or abnormalities in the innermost layers of the esophagus, stomach, and small intestine.

What treatments are suggested for black stools?

Treatment of black stools depends on the underlying cause, but may include:

  • If the cause of the dark stools is due to foods or medications, immediately stopping those foods and drugs helps get normal stools.
  • If the cause of black stools is gastrointestinal ulcers, the proton inhibitors and ulcer protective agents may help treat black stools.
  • The decreased usage of nonsteroidal anti-inflammatory drugs, steroids, and spicy foods may help reduce intestinal ulcers.
  • Surgery is recommended in severe cases of intestinal ulcers that do not respond to medical therapy, have perforated, or are a result of a tumor in the gastrointestinal area.

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Medically Reviewed on 10/5/2022
References
Image Source: iStock image

Why Is Your Poop Black and Tarry? https://www.webmd.com/digestive-disorders/black-tarry-stool-reasons

Black or tarry stools. https://medlineplus.gov/ency/article/003130.htm

Rectal Bleeding. https://my.clevelandclinic.org/health/symptoms/14612-rectal-bleeding