Black Stool
Black stool can be a surprising sight, and many people want to know when it is a cause for concern. While black stool can sometimes happen after eating certain foods or taking iron supplements, it can also be a sign of something more serious.
If black stool is tarry, has a strong smell, or occurs with other symptoms like stomach pain or weakness, it may mean there is bleeding in the digestive tract and you should see a doctor right away.
Not every case of black stool is an emergency, but knowing the difference between harmless and dangerous causes helps you stay healthy and avoid missing a serious problem.
Definition Of Symptom
Black stool means your poop looks dark or even black instead of the usual brown color. You might notice this change on toilet paper or in the toilet bowl. Many times, black poop comes from what you eat, like dark-colored foods or iron supplements. However, sometimes it signals something happening inside your digestive system.
Doctors use the term melena when black stool is sticky and smells strong. Melena often means bleeding in the upper part of the digestive system, such as the stomach or esophagus. Blood turns black after mixing with stomach acids and moving through the intestines. The table below shows what black stool may look like and what it could mean:
| Appearance | Possible Cause |
|---|---|
| Black and sticky | Bleeding in upper digestive tract (melena) |
| Black, non-sticky | Iron supplements, bismuth, dark foods |
| Black with foul odor | Possible internal bleeding |
Pay attention if black stool happens along with other symptoms like heartburn, indigestion, dizziness, or stomach pain. These can give more clues about digestive health.
Possible Causes/ Diseases Condition
Several things can cause black stool, ranging from harmless to serious. Bleeding in the upper digestive tract often causes the color, but certain foods or medications can also be responsible. Common medical causes include:
- Peptic Ulcers: Open sores in the stomach or upper intestine can bleed and turn stool black.
- Gastrointestinal Bleeding: Bleeding in the esophagus, stomach, or small intestine may lead to dark or tar-like stools.
- Esophageal Varices: Swollen veins in the esophagus from liver disease can rupture and bleed.
- Gastritis: When the stomach lining gets inflamed, it may bleed and cause dark stools.
- Mallory-Weiss tear: A tear at the junction of the stomach and esophagus can cause bleeding after severe vomiting.
- Colon Polyps and Colorectal Cancer: Rarely, bleeding from large polyps or tumors can change stool color.
Other related conditions:
- Liver Disease: Problems with the liver, such as cirrhosis, can lead to bleeding in the digestive system.
- Angiodysplasia: Fragile blood vessels in the gut may bleed slowly or suddenly.
- Helicobacter Pylori Infection: This bacteria can cause ulcers and increase bleeding risk.
- Gastroesophageal Reflux Disease (GERD): Although less common, GERD can sometimes result in blood loss if severe.
| Condition | Is Bleeding Common? | Other Symptoms |
|---|---|---|
| Peptic Ulcer | Yes | Pain, nausea |
| Esophageal Varices | Yes | Vomiting blood |
| Gastritis | Yes | Indigestion, pain |
| Colorectal Cancer | Sometimes | Weight loss, changes in stool |
| Mallory-Weiss Tear | Yes | Vomiting, pain |
| Angiodysplasia | Sometimes | Weakness, fatigue |
Other Non-Disease Causes
Some foods and medications may turn stool black, even if there is no disease present. This is a common reason for dark-colored poop and can be managed by simply avoiding the trigger. Common foods that can darken stool:
- Black licorice
- Blood sausage
- Blueberries
- Dark-colored foods like chocolate cake
- Beets (though these also sometimes turn stool red)
Common Medicines and Supplements
| Item | Common Use |
|---|---|
| Iron supplements | Treating low iron |
| Bismuth subsalicylate | Stomach relief |
| Aspirin, ibuprofen, NSAIDs | Pain relief |
| Blood thinners | Preventing blood clots |
| Proton pump inhibitors | Reducing stomach acid |
Iron supplements often make stool black and usually aren’t a cause for worry unless other symptoms appear. Bismuth subsalicylate, found in some stomach medicines, can also cause this color change.
Pain relievers like aspirin, ibuprofen, and other NSAIDs sometimes lead to black stool. This can happen because of the medication itself or from irritation in the stomach. Certain blood thinners may rarely lead to dark or black stool because they affect bleeding.
How It Causes The Symptom
Black stool happens when something in the digestive tract changes the color of poop. Bleeding in the upper part of the digestive tract, like the stomach or esophagus, often causes this. Blood turns black as it moves through the intestines.
Some foods, such as black licorice or blueberries, and iron supplements can also make stool black. These usually do not cause other digestive issues. Common causes of black stool include:
- Upper digestive tract bleeding (such as ulcers or tears)
- Dark-colored foods and drinks
- Certain medications (like iron pills or medicines containing bismuth)
When blood causes the stool to appear black, it may also be sticky or tar-like. This is called melena and often comes with other symptoms:
| Symptom | Description |
|---|---|
| Nausea | Feeling sick to the stomach. |
| Abdominal pain | Pain or cramps in the belly, which can be mild or severe. |
| Bloating | Stomach feels full or swollen. |
| Diarrhea | Frequent, loose, or watery bowel movements. |
| Constipation | Trouble passing stools or less frequent bowel movements. |
| Change in bowel habits | Any new or unusual pattern in going to the bathroom. |
You may notice weakness, dizziness, or a faint feeling if you lose a lot of blood. If a harmless food or medicine causes the black stool, you usually won’t have pain, nausea, or other digestive problems.
Possible Complications
Black stool can signal several serious health problems, especially if bleeding in the digestive tract causes it. Blood loss is a major risk. Ongoing bleeding can cause anemia. Signs of anemia include weakness, shortness of breath, and tiredness.
Sudden or ongoing blood loss might cause low blood pressure or even shock, especially if the bleeding is heavy or not treated quickly. Unexplained weight loss along with black stool can point to conditions like stomach ulcers or cancer. Unintentional weight loss always needs medical attention. Possible complications linked to black stool include:
- Anemia (low red blood cell count)
- Drop in blood pressure
- Fainting or dizziness
- Ongoing stomach pain
- Severe fatigue
- Gastrointestinal ulcers or tumors
Medicines or iron supplements sometimes cause black stool without other complications. But when bleeding causes the color change, it can be dangerous.
When To Seek Medical Attention
Black stool can sometimes result from harmless factors like certain foods or medications. However, it may also signal bleeding in the digestive tract, which requires quick action. Contact a doctor right away if you notice black stool along with any of these symptoms:
- Severe or ongoing abdominal pain
- Vomiting blood or material that looks like coffee grounds
- Feeling dizzy, weak, or faint
- Trouble breathing
- History of gastrointestinal bleeding or ulcers
Doctors may use tests like endoscopy or colonoscopy to find the source of bleeding or other problems inside the stomach or intestines. People with other health issues, such as liver disease or cancer, should act quickly and contact their care team if they notice black stool.
A gastroenterologist can help diagnose and treat digestive tract problems, including unexplained black stool. If you don’t know the cause, or if black stool lasts more than a few days, visit a medical professional.
