WHY IS MY POOP BLACK? WHAT’S NORMAL AND WHEN TO WORRY

Medically reviewed by Robert Burakoff, MD

Key Takeaways

• Black poop can be caused by certain foods or medications.
• Stool may also be black because of blood in the digestive tract, known as melena. 
• A small drop of red blood is usually due to minor hemorrhoids but could be a serious lower GI issue.

Black poop is often a harmless result of certain foods or medications, but sometimes it can be a sign of blood in your stool. If black stool persists or happens with stomach pain, vomiting, or other symptoms, see a healthcare provider right away.

Foods that Turn Poop Black

If you have recently eaten a large portion of dark or black-colored foods, your poop can look black, too.

Some foods or ingredients may be more likely than others to make your poop look black, such as:

• Black licorice
• Blueberries
• Blood sausage
• Dark chocolate
• Chocolate sandwich cookies
• Dark beer
• Dark leafy vegetables
• Beets
• Grape juice
• Foods or drinks that contain artificial coloring

If you notice black stool after eating one of these items, and you are not experiencing any other new or unusual symptoms, wait and see if the stool color returns to normal after another bowel movement. If it doesn’t, or if the stool looks black and tarry, contact your healthcare provider.

How Dark Is Too Dark for Poop?

Normal stool ranges from brown to greenish-brown, and dark brown is usually harmless. However, black, red, or tarry stool warrants medical attention. Black flecks or spots in otherwise normal stool have the same causes as fully black stool—harmless foods or a small amount of melena. If it persists for more than a few bowel movements, consult a healthcare provider.

Medications and Supplements

Black stools could be caused by supplements and medications. Some of the most common types include:

• Iron supplements: When iron from supplements that has not been absorbed in your gut mixes with the microbiome in your digestive tract, it can cause your stool to turn a black color.
• Bismuth subsalicylate: This is the main active ingredient in Pepto-Bismol. It turns into bismuth sulfide when it mixes with the sulfur in your digestive tract. Bismuth sulfide is black, and as it passes through your digestive tract, it can turn your stool black as well.
• Activated charcoal: This black, powder-like substance is often used to treat poisoning, but it’s available as a supplement. It is not absorbed by the gut, so as it passes through the digestive system, it can cause your poop to look black.

While black poop is fairly common with any of these, it’s not common for the poop to look black and have a texture like coffee grounds or wet asphalt.

If you think a medication or supplement is turning your poop black, call your healthcare provider. They can confirm if it’s a normal side effect or if you need an evaluation.

Can Dehydration Cause Black Poop?

Dehydration alone usually doesn’t cause black stools. If your stool appears black and tarry or you’re unsure, contact your healthcare provider for advice.

When Melena Turns Poop Black

Black poop can be a sign of melena, which means there’s blood in your stool. In melena, blood turns black as it moves through the body. Digestive enzymes break it down in the tract, changing its color and texture.

If you notice bright red blood in your stool (hematochezia), it most likely comes from the lower digestive tract, such as the rectum or colon. Because it undergoes minimal digestion, it remains red rather than turning black.

Bright red blood in the stool could be due to a minor issue like a hemorrhoid. But any form of blood in the stool should be checked if it persists or is accompanied by other symptoms.

Feature	Harmless Black Poop	Melena
Causes	Supplements, medications, and dark-colored foods	Internal bleeding, often from the upper digestive tract
Color	Dark brown to black	Jet black, tarry, or coffee ground-like
Texture	Firm or soft; normal stool consistency	Sticky, shiny, and often loose
Odor	Normal stool odor	Strong, foul, metallic-smell due to digested blood
Duration	Temporary; stops once the trigger is removed	Persists or worsens over time

Symptoms That May Accompany Melena

If you’re uncertain whether black stool is melena, look for additional signs of internal bleeding, including:

• Stomach or chest discomfort
• Nausea, vomiting, or diarrhea
• Weakness or lightheadedness
• Dizziness or fainting

You might also experience symptoms specifically related to the underlying cause of the melena. If there’s any doubt, it’s best to see a healthcare provider right away.

A Guide to Digestive Causes of Melena

Specific gastrointestinal diseases or conditions can lead to black stools.

Gastritis and Bleeding Ulcers

Gastritis is inflammation of the stomach lining, often triggered by alcohol, smoking, infections, trauma, or prolonged use of NSAIDs like ibuprofen or aspirin. In some cases, gastritis can cause minor bleeding, but when it worsens, it can lead to more serious damage.

If gastritis is untreated or becomes severe, it can lead to hemorrhagic erosive gastropathy—a condition where the stomach lining develops open wounds (erosions) that actively bleed. This bleeding can result in melena.

Another possible outcome of chronic gastritis is the development of peptic ulcers, which are sores in the stomach lining. These ulcers often form when stomach acid erodes weakened tissue, especially in people who:

• Take NSAIDs frequently, which thins the stomach’s protective barrier
• Consume excessive alcohol, which irritates and weakens the stomach lining
• Experience bile reflux, where digestive fluids from the liver back up into the stomach
• Have a Helicobacter pylori infection (H. pylori), a common bacterial cause of stomach ulcers
• Have severe illness or stress-related conditions that reduce blood flow to the stomach

A bleeding ulcer can lead to melena if the blood has time to be digested, turning stools black and sticky. If the bleeding is rapid or severe, it may cause vomiting blood or bright red stools instead.

Esophagitis

In some cases, bleeding that leads to melena may not come from the stomach but rather from esophagitis, an inflammation of the esophagus.

Esophagitis can be caused by:

• Acid reflux
• Infections
• Irritation from medications
• Chronic vomiting
• Medical procedures, such as radiation therapy
• Allergies, often to food

If severe enough, it can lead to esophageal ulcers that may bleed and cause melena.

Esophageal Varices

Esophageal varices are enlarged veins in the wall of the lower esophagus or upper stomach. When these veins rupture, they may cause bleeding in the esophagus and lead to blood in the stool or in vomit.

Esophageal varices are a serious complication of high blood pressure in the portal vein, most often caused by liver cirrhosis. Most people with esophageal varices experience no symptoms unless the veins rupture.

Bleeding esophageal varices require immediate medical care to stop the bleeding, as they can lead to sudden death.

Mallory-Weiss Tear

A Mallory-Weiss tear is a tear in the mucous membrane where the esophagus meets the stomach. If it bleeds, it can cause melena. Most cases result from forceful vomiting, coughing, or straining. Mallory-Weiss tears account for about 5% to 15% of gastrointestinal bleeding cases.

Like other conditions that cause melena, symptoms of a Mallory-Weiss tear may not be obvious. When symptoms due occur, they may resemble the symptoms of internal bleeding.

Liver Disease

Liver disease can damage the veins that move blood into the liver. This can cause pressure to build up in the veins, eventually causing them to burst. When this happens, you may vomit blood or have black, tarry stool.

Other signs of end-stage liver disease include:

• Jaundice (yellowing of the skin and eyes)
• Confusion or other mental difficulties
• Swelling in the belly, arms, or legs
• Severe fatigue
• A tendency to bleed easily

Gastrointestinal bleeding is considered a sign of end-stage liver disease, along with bleeding from the nose and gums. This bleeding can be life-threatening, so you should see an emergency medical provider right away.

Upper GI Cancers

Cancers that cause gastrointestinal (GI) bleeding such as esophageal, stomach, or pancreatic cancer can also have black, tarry stools as a symptom.

These cancers often have other symptoms such as:

• Swallowing problems
• Poor appetite
• Indigestion or heartburn
• Unintentional weight loss
• Vague discomfort around the navel
• Feeling full after only eating a small meal
• Vomiting with or without blood
• Swelling or fluid buildup in the abdomen
• Fatigue
• Pain in the chest or stomach
• Coughing
• Nausea or vomiting

Many GI cancers do not cause noticeable symptoms until advanced stages. If you are experiencing any of these symptoms in addition to black stool, see a healthcare provider right away.

Viral Hemorrhagic Fever

Viral hemorrhagic fevers (VHFs) are a group of illnesses caused by specific viruses that can lead to bleeding disorders.

These viruses affect the body’s blood vessels, making them more prone to leakage and causing internal bleeding. When this bleeding occurs in the digestive tract, it can result in melena.

Types of viral hemorrhagic fevers include:

• Ebola virus disease: Known for causing severe bleeding and organ failure.
• Marburg virus disease: Similar to Ebola, it leads to severe hemorrhagic fever.
• Dengue hemorrhagic fever: A severe form of dengue fever that can cause bleeding, blood plasma leakage, and low platelet count.

Viral hemorrhagic fevers are rare in developed countries. They are usually spread through contact with infected animals or insects, like mosquitoes and ticks, or by direct exposure to an infected person’s bodily fluids.

How Causes of Black Poop Are Diagnosed

To figure out why your poop is black, a healthcare provider will ask about your symptoms, diet, and any medications or supplements you take. They might do a stool test to check for hidden blood. If they suspect bleeding:

• They may do an endoscopy, where a small camera on a flexible tube looks inside your stomach and intestines.
• If the bleeding is lower in your digestive system, they might use a colonoscopy instead.
• Imaging tests like a CT scan or angiography (a scan of your blood vessels) help find the exact source of bleeding.

Blood tests can also check for anemia, which happens when you’ve lost too much blood.

Treating Underlying Conditions

Melena is a symptom of an underlying condition, not a condition itself, so there’s no specific treatment for black stool alone.

If food is the cause, avoiding it should return your stool to its normal brown color within a day or two. If a medication is to blame, the discoloration will stop once you discontinue it.

With that being said, if the medication was prescribed or recommended by a healthcare provider, check with them before stopping it.

If the black poop is true melena, the treatment depends entirely on the condition causing it:

• Gastritis: The standard treatment is antacids or medications called proton pump inhibitors that work by neutralizing stomach acid to allow the stomach lining to heal. If it’s caused by an H. pylori infection, your provider may prescribe antibiotics.
• Bleeding ulcers: Treatment may involve an endoscopy to seal the ulcer. If bleeding continues, the provider might block the blood vessel with an angiography or perform surgery. If H. pylori is the cause, antibiotics can help clear the infection.
• Esophagitis: If acid reflux is causing the inflammation, your provider may recommend antacids and lifestyle changes like avoiding spicy foods. If an infection is responsible, antibiotic medicine will clear it up. Bleeding or narrowing in the esophagus is treated with surgery.
• Esophageal varices: These swollen veins in the esophagus can burst and cause serious bleeding. Providers stop the bleeding by tying off the veins with bands or prescribing medication to lower pressure and prevent future problems.
• Mallory-Weiss tear: Many cases heal on their own. However, heavy bleeding may require an endoscopy to stop it with clips or cauterization. Avoiding heavy drinking can help reduce the risk of future tears.
• Liver disease: Treatment focuses on managing liver disease. This may involve medications, dietary changes like a low-sodium diet, or, in severe cases, a liver transplant.
• Upper GI cancers: Treatment depends on the stage and type of cancer. Providers use surgery, chemotherapy, radiation, or targeted drug therapy to shrink or remove tumors. Early detection improves the chances of successful treatment.
• Hemorrhagic fevers: Generally, there is no known cure for these diseases. Doctors focus on managing symptoms with fluids for hydration and medications to control fever and pain. Some cases require antiviral drugs and hospital care.

Once the underlying cause of melena is treated, the bleeding should stop, and your stool will gradually return to its normal color.

When to See a Healthcare Provider

If your stool appears black but you have no other symptoms, contact your healthcare provider for guidance. Since black stool can indicate internal bleeding, your provider may recommend an immediate evaluation.

Seek urgent medical attention if you experience any of the following:

• Black stool with a sticky consistency and strong, unpleasant odor
• Vomiting blood or vomit that resembles coffee grounds
• Dizziness, weakness, or lightheadedness
• Heart palpitations or shortness of breath
• Black stools lasting more than a day or two

A small spot of bright red blood in your stool may be caused by minor issues like an anal fissure or hemorrhoid, and is not always a cause for concern. In children, a small amount of blood in the stool is most often not serious and usually caused by constipation.

However, if the bleeding continues, worsens, or is accompanied by other symptoms like pain, dizziness, or changes in bowel habits, see a healthcare provider as soon as possible to rule out any serious conditions.

Read the original article on Verywell Health

2024-08-22T21:22:14Z