Why Do I Have Black Stools After Having Diarrhea?

Black or tarry stools may indicate a change in diet or a medical issue. Black stool is a sign of older blood in the stool, which turns black and tarry while traveling through the gastrointestinal tract. Digestive chemicals interact with the blood during its journey, changing its color and texture. Black stools with a foul smell are often a sign of a problem in the upper digestive tract, most often indicating bleeding. Black poop can be caused by medications, supplements, or dark foods like beets or black licorice. Black stools can be caused by internal bleeding, but the active ingredient, bismuth subsalicylate, can cause the stool to turn black or gray. Black stools can be caused by bleeding in the digestive system (stomach, duodenum, etc.), but black stools in gastrointestinal bleeding are usually temporary. One of the most serious black stool causes is bleeding in the GI tract, known as melena. This type of black poop is often very sticky with a foul smell.

Why is my poop black after taking anti diarrhea?

One common side effect is your poo or your tongue turning black. This is harmless.

This happens when bismuth (the active ingredient in this medicine) comes into contact with small amounts of sulphur in your saliva and digestive system. They combine to form bismuth sulfide, a black substance. As it slowly makes its way out of your body you may see black poo.

This side effect usually goes away when you stop taking the medicine but it may take several days.

If your tongue or your poo is still black after you’ve stopped taking Pepto-Bismol for several days, speak to your doctor or a pharmacist.

Can black stools be harmless?

Black poop often has harmless causes such as medications, supplements, or dark foods like beets or black licorice.

While black poop isn’t always something to worry about, it can occasionally be an indication that there is blood in your upper gastrointestinal system. This could mean a serious underlying health condition such as liver disease or cancer.

Illustration by Michela Buttignol for Verywell Health.

If your stool is black and tarry (a sticky consistency), it means there is blood in it. This is a medical emergency.

Can food poisoning cause black stool?

There are a number of different conditions that can cause diarrhea, including irritable bowel syndrome, food poisoning, and gastrointestinal infections. Black colored stools are a sign of bleeding into the digestive tract. Any bleeding in the digestive tract should be evaluated by a physician to determine the cause. If you experience black colored stools and diarrhea, seek the advice of your healthcare provider to determine the cause.

While the list below can be considered as a guide to educate yourself about these conditions, this is not a substitute for a diagnosis from a health care provider. There are many other medical conditions that also can be associated with your symptoms and signs. Here are a number of those from MedicineNet:

Peptic Ulcer. Peptic or stomach ulcers are ulcers in the lining of the stomach, duodenum, or esophagus. Learn about symptoms, causes, diet, and treatment.

Is black diarrhea an emergency?

When should you worry about black stool? If your black stool looks tarry or sticky and has a strong smell, it might be melena. Melena means you’re bleeding somewhere inside. Internal bleeding is always serious, especially when you can’t tell if it’s stopped.

What causes melena (black stool)?. Melena comes from bleeding in your upper GI tract — usually your stomach or the upper part of your small intestine (duodenum). It could also be from your lower esophagus if you swallowed the blood. Rarely, it might be from your lower small bowel or upper large bowel, if your bowels move very slowly.

Causes of upper GI bleeding and melena may include:

What are other causes of black stool (besides melena)?. Certain medicines, supplements and foods may stain your stool black, including:

Can dehydration cause black poop?

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.

Can dehydration cause black stool?

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.

How long does it take for black stools to go away?

Black poop can also happen with more minor incidents, like with diets that are rich in iron or in people who take iron supplements. Some medication can also cause darker stools. Nonetheless, if your black poop persist for more than 2 days, you should see your doctor for assessment.

Black poop is usually caused by blood that has gone through the digestive track and is eliminated in the stool. It is often a sign of bleeding specifically at the beginning of the digestive tract, near the esophagus or stomach. Bleeding in these areas can occur due to ulcers or varices.

Black poop can also be caused by more minor conditions, like iron-rich diets or from iron supplements. Some medication can also lead to darker stools.

What color is poop after diarrhea?

If stool passes through the intestine too quickly, there might not be enough time for bile to be digested and broken down to provide the normal brownish stool color. Normally, bacteria in the intestine chemically change bile to a greenish-brown color. It takes time for the bile to fully revert in the intestine and become brown again, and if the transit time is short, for example, when a person has diarrhea, the stool remains green-colored.

Green stools may be a normal variant. A diet rich in green vegetables, especially spinach, or iron supplements also may cause green poop, though iron often turns stool black.

There are a variety of reasons why stool will be yellow, greasy, and foul-smelling. It can be due to the intestine’s inability to digest and absorb fat, which may result from diseases of the intestinal lining (such as celiac disease and cystic fibrosis), the inability of the pancreas to manufacture adequate digestive enzymes (such as with chronic pancreatitis or pancreatic cancer that blocks the pancreatic duct), or inadequate bile being delivered to the intestine (such as in cancer of the liver or bile ducts that are blocked). The yellowness, greasiness, and foul smell are due to the undigested fat.

The most common cause of bright red-colored stool in adults is bleeding from hemorrhoids. One of the most concerning causes is bleeding in the gastrointestinal tract. Although this usually presents with dark, black stool, it can also cause bright red blood. This will require urgent evaluation by a health care provider. In infants, the most common cause is an anal fissure or tear in the tissue surrounding the anus.

What are 3 causes of black stool?

Black and tarry stools may also occur due to:Abnormal blood vessels in the esophagus, stomach, or duodenum. A tear in the esophagus from violent vomiting (Mallory-Weiss tear)Blood supply being cut off to part of the intestines. Inflammation of the stomach lining (gastritis)Trauma or foreign body.

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.

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.

Is black poop normal after a stomach bug?

• The greatest risk is dehydration. You must keep up your fluid intake!
• When accompanied by vomiting and/or fever, chances of becoming dehydrated are increased.
• Black or bloody diarrhea may signal bleeding from the stomach or intestines. However some medications can also turn the stool black, (especially Pepto-Bismol).
• Cramping or intermittent gas-like pains are not uncommon, however, steady persistent abdominal pain is not!

• Decreased urine output or very dark urine.
• marked thirst
• dry mouth
• sunken looking eyes sometimes with dark circles
• skin that has lots its elasticity (to check this pinch skin on the stomach or the back of the hand using all 5 fingers. When released it should spring back immediately, compare to another person’s if necessary. When skin remains tented and does not spring back normally, dehydration is indicated).

Can food poisoning make poop black?

There are a number of different conditions that can cause diarrhea, including irritable bowel syndrome, food poisoning, and gastrointestinal infections. Black colored stools are a sign of bleeding into the digestive tract. Any bleeding in the digestive tract should be evaluated by a physician to determine the cause. If you experience black colored stools and diarrhea, seek the advice of your healthcare provider to determine the cause.

While the list below can be considered as a guide to educate yourself about these conditions, this is not a substitute for a diagnosis from a health care provider. There are many other medical conditions that also can be associated with your symptoms and signs. Here are a number of those from MedicineNet:

Peptic Ulcer. Peptic or stomach ulcers are ulcers in the lining of the stomach, duodenum, or esophagus. Learn about symptoms, causes, diet, and treatment.