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Quick Insight Into Digestive Tract Processes and Stool Color

The digestive system in the human body consists of the gastrointestinal tract (GI tract) and solid organs such as the liver, gallbladder, and pancreas. The GI tract is a long, thin tube including the mouth, esophagus, stomach, small intestine, large intestine, and anus.

The food you eat moves through your digestive system, where it is broken down into smaller particles and liquid. Your body needs to digest food to absorb nutrients. The remaining waste products become stool and are eliminated from your body. 

Normal Stool Color 

Normal stool is various shades of brown, sometimes with a green tinge. Stool color depends on two major things - what you eat and the amount of bile present in your stool. 

Bile is a yellow-green substance made by the liver and stored in the gallbladder. It helps to digest fats. As bile goes through your gastrointestinal tract, it is chemically altered by enzymes. This changes the color of bile from yellow-green to brown. When mixed with food waste, it gives poop its usual brown color.

Significance of Stool Color 

Changes in stool color rarely indicate serious gastrointestinal conditions. For example, black and tarry stools are often the result of eating dark-colored foods or taking certain medications. However, sometimes, black stools (the medical term is melena) indicate a more serious problem, such as bleeding in the upper digestive tract.

Common Causes of Black Poop

Foods That Can Make Stool Black

Eating certain black foods such as black licorice, blood sausage, and blueberries can make your poop dark or black-colored. Beets and foods containing red food coloring can also give your stool a dark color.

Medications and Supplements

Taking iron supplements and medications such as bismuth subsalicylate (Pepto-Bismol, Kaopectate) can give you black stools.

Health Issues

Upper Gastrointestinal Bleeding

Black and tarry stools can be a sign of bleeding in the upper gastrointestinal tract (esophagus, stomach, or duodenum - the first part of the small intestine). Health conditions that can cause upper GI bleeding include: 

• Stomach ulcers — sores in the stomach lining that can develop due to a bacterial infection with Helicobacter pylori (H. pylori) — or overuse of nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen.

• Esophageal varices (enlarged veins in the esophagus caused by liver cirrhosis).

• Mallory Weiss tear (a tear in the esophagus typically caused by violent vomiting or intense coughing).

The black color of poop is from the blood, which gets digested as it travels through the GI tract. In contrast, bright red blood in stool is a sign of active bleeding in the lower GI tract (rectum and anus).

Other Conditions of the Gastrointestinal Tract

Black stools may also be present in medical conditions such as:

• Abnormal blood vessels in the upper GI tract.

• Blocked blood supply to a part of the intestines.

• Gastritis (stomach inflammation).

• Foreign body or trauma to the GI tract.

• Cancer of the esophagus, stomach, or first part of the small intestine.

Liver Disease and Its Impact on Stool Color

As mentioned, the liver makes bile, which gives stool its normal brown color. People with liver problems may have reduced bile production, which can result in pale or clay-colored stools. Light-colored stools can also be a sign of a blockage in the flow of bile. Clay-colored stools are frequently accompanied by yellowing of the skin (jaundice), which occurs due to a buildup of bile salts in the body. 

Other Symptoms to Watch For Alongside Black Stool

Implications of Tarry Stools

Black and tarry stools can be a harmless result of something you ate. However, they can also indicate a more serious problem. That’s why it’s important to see your healthcare provider without delay if you notice blood in your stool or black stools.

Accompanying Symptoms That May Indicate Serious Conditions

Make an appointment to see your doctor if you have more severe symptoms accompanying black, tarry stools, such as:

• Dizziness or lightheadedness (this may be due to low blood pressure caused by blood loss).

• Vomiting blood or vomit that looks like coffee grounds.

• Severe stomach pain.

• Changes in bowel movement patterns.

Diagnostic Studies for Black Stools

Your doctor will obtain a medical history, perform a physical exam, and order tests to find out what is making your stool black. Some of the investigations that can help to identify the cause of black poop include:

• Stool test (fecal occult blood test)

• Blood tests

• Testing for H. pylori

• X-ray

• Upper endoscopy or esophagogastroduodenoscopy (EGD)

• Colonoscopy

• Nuclear medicine scan

A procedure such as upper endoscopy can be both diagnostic and therapeutic. For example, it can be used for injecting medication directly into a lesion or clipping a bleeding blood vessel.

Black Poop Remedies

Home Remedies and Dietary Adjustments

Once your doctor has evaluated you and determined that your black poop isn’t serious, the following home remedies may help:

• Avoid eating dark foods that can make your poop black. Also, avoid acidic and spicy foods that can cause an upset stomach and make symptoms of gastric ulcers worse.

• Increase your fluid intake and consume fiber-rich foods. This can help prevent constipation. Straining due to constipation can lead to blood in your stool.

• Consider taking probiotics to optimize digestive health. Probiotics are healthy live bacteria that help to rebalance the gut microbiome.

• Try herbal remedies such as ginger, peppermint, and turmeric, which may benefit digestion because of their anti-inflammatory properties. However, if you are taking other medications, make sure to check with your doctor before using herbal supplements to avoid harmful drug interactions. 

Treatment Options for GI Bleeding and Other Causes of Black Stools

Over-the-counter and Prescription Medications 

According to the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK), treatment for dark stools depends on the cause. 

For example, if you have stomach ulcers, your provider may prescribe medications called proton pump inhibitors, such as omeprazole (Prilosec), pantoprazole (Protonix), lansoprazole (Prevacid), and others. These drugs reduce the amount of acid produced by the stomach, thereby preventing further damage to the stomach lining while the ulcers heal.

Your healthcare provider may also prescribe a medicine, such as sucralfate, that forms a protective covering on the stomach lining. This prevents damage from irritants such as stomach acid, nonsteroidal anti-inflammatory drugs, and alcohol.

If you have esophageal varices, your healthcare provider may prescribe drugs called beta blockers (propranolol, nadolol, and others). These medicines help to lower blood pressure in the portal vein and reduce the risk of bleeding varices. 

Surgery and Other Interventions

If you have lost a lot of blood due to internal bleeding, you may need a transfusion of red blood cells. 

Surgery is usually only necessary in severe cases. For instance, if you have had bleeding from esophageal varices, your healthcare provider may recommend a procedure called endoscopic band ligation.

Frequently Asked Questions

Is black poop an emergency?

Black stool that looks sticky or tarry and has a strong smell might be the result of bleeding in your GI tract. Bleeding anywhere inside the body is always serious because you may not be able to tell if it has stopped. It is especially important to seek emergency medical care if, along with black poop, you vomit blood or have accompanying symptoms such as dizziness, fainting, or abdominal pain.

Can black poop be temporary?

Yes, black poop can be temporary if it is caused by dark-colored foods or if you are taking iron pills or medications containing bismuth.

How do you fix black poop?

The fix for black poop depends on the cause. It’s important to consult your healthcare provider so that they can rule out serious problems such as upper GI bleeding.

Can dehydration cause black stool?

Dehydration can cause drier stool that is darker brown in color and may appear black.

What does stress poop look like?

Stress and anxiety do not usually affect stool color. However, stress can affect bowel function and may cause constipation or diarrhea in some people.