Black Stools and Upper GI Bleeding: What It Means

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Black stools that are also sticky, tarry, and unusually foul-smelling are one of the main signs of bleeding in the upper digestive tract: the esophagus, the stomach, or the first part of the small intestine. Doctors call this melena. Black stools can also have harmless causes, such as iron pills or a bismuth medicine like Pepto-Bismol, and telling the two apart is not something to do by guesswork. This page is for adults in Arlington, Annandale, and the rest of Northern Virginia who have noticed black stools, or who had a bleeding episode and want to understand the follow-up. It explains what black stools can mean, what causes upper GI bleeding, how it is evaluated, and when it is an emergency.

If you have black, tarry stools along with dizziness, lightheadedness, fainting, a fast heartbeat, shortness of breath, confusion, or cold and pale skin, call 911. The same is true if you are vomiting blood or material that looks like coffee grounds. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) warns that severe GI bleeding can lead to shock, which is life-threatening. Do not drive yourself, and do not wait to see whether it happens again.

This article is general education, not medical advice. It cannot tell you whether your own black stools are from bleeding.

What black stools can mean

Blood changes color as it moves through the digestive tract. MedlinePlus, the National Library of Medicine's consumer health service, explains that blood from the esophagus, stomach, or first part of the small intestine turns darker because it gets digested on the way down. By the time it leaves the body, it can look black and tarry, and MedlinePlus describes black or tarry stools with a foul smell as a sign of a problem in the upper digestive tract.

Red blood is different. Bright red blood in or on the stool most often comes from lower in the tract, the colon, rectum, or anus, and our page on blood in stool and rectal bleeding covers that symptom. This page owns the black and tarry kind. The line between the two is not perfectly clean. The 2021 American College of Gastroenterology (ACG) guideline on upper GI and ulcer bleeding lists three signs of overt upper GI bleeding:

• Hematemesis: vomiting red blood or material that looks like coffee grounds
• Melena: black, tarry stool
• Hematochezia: passing red or maroon material from the rectum, which usually points lower in the tract but can also come from an upper GI bleed

Black stools can also come and go. NIDDK notes that slow, ongoing bleeding may produce stool that is sometimes black and tarry and sometimes mixed with red blood, and that over time this kind of bleeding can lead to anemia.

What else turns stools black

Not every black stool means blood. MedlinePlus lists several common causes that have nothing to do with bleeding:

• Iron pills
• Medicines that contain bismuth, such as Pepto-Bismol
• Activated charcoal
• Black licorice, blueberries, and blood sausage

Bismuth is the one people most often run into. The over-the-counter label for bismuth subsalicylate, on file at the National Library of Medicine's DailyMed, states that a temporary but harmless darkening of the stool or tongue may occur. The same label also says not to use the product if you have an ulcer, a bleeding problem, or bloody or black stool, and to ask a doctor first if you take a blood thinner. Bismuth subsalicylate is a salicylate, related to aspirin. So it is not a good idea to reach for it to settle a stomach after noticing black stools you cannot explain.

How do you tell the difference? Often you cannot by looking. MedlinePlus notes that a clinician can test the stool chemically for blood. If you have started iron or taken bismuth and your stools are dark but you feel well, it is still reasonable to mention it to your doctor. If you have not taken either, if the stools are tarry, or if you feel unwell at all, treat it as possible bleeding.

Causes of black stools from upper GI bleeding

NIDDK and MedlinePlus list the same main causes of bleeding in the esophagus, stomach, and duodenum.

Peptic ulcers

MedlinePlus calls peptic ulcers the most common cause of acute upper GI bleeding, and the ACG guideline describes ulcer bleeding the same way. These are open sores in the lining of the stomach or duodenum. NIDDK names the most common causes of peptic ulcers as Helicobacter pylori (H. pylori) infection and taking nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen, and naproxen, along with blood thinners. Ulcers do not always hurt, so black stools can be the first sign of one.

Gastritis and esophagitis

Gastritis is inflammation or damage of the stomach lining, and NIDDK notes it can lead to shallow breaks or ulcers that bleed. Its causes overlap with ulcers: H. pylori, NSAIDs, blood thinners, and alcohol. Esophagitis, inflammation of the esophagus, can also bleed, and NIDDK notes it is often caused by GERD.

Varices

Varices are enlarged veins in the esophagus or stomach. NIDDK explains that they can bleed if they burst and are most often related to cirrhosis, because scarring of the liver backs up blood flow into these veins. Variceal bleeding can be heavy. Anyone with known liver disease who notices black stools or vomits blood needs emergency care.

Mallory-Weiss tears

These are tears in the lining of the lower esophagus, and NIDDK notes they are often caused by severe vomiting. Bleeding that starts after a bout of forceful vomiting or retching fits this pattern, though other causes are still possible.

Tumors

Benign tumors and cancers of the esophagus or stomach can weaken the lining and expose blood vessels, according to NIDDK. The American Cancer Society lists dark or black stools among the possible symptoms of stomach cancer. This is not the most likely explanation for black stools, but it is one reason they always deserve an answer.

Abnormal blood vessels and other causes

MedlinePlus also lists abnormal blood vessels in the lining of the upper tract, loss of blood supply to part of the intestine, trauma, and swallowed foreign objects. NIDDK adds that bleeding from the small intestine, beyond the reach of a standard upper endoscopy, can come from abnormal or enlarged blood vessels called angiodysplasia.

Medicines that raise the risk of bleeding

Several common medicines make upper GI bleeding more likely or more severe. NIDDK lists NSAIDs, available both over the counter and by prescription, and blood thinners, and notes that the risk is higher in people who take blood thinners together with NSAIDs or aspirin, and in people who have had GI bleeding before. MedlinePlus adds that anticoagulant and antiplatelet medicines, the two main kinds of blood thinners, increase the risk of GI bleeding.

If you take any of these and notice black stools, do not stop a prescribed blood thinner or aspirin on your own. For some people, stopping one can cause a stroke or heart attack. The 2022 ACG and Canadian Association of Gastroenterology guideline on blood thinners during GI bleeding suggests that people who take aspirin to prevent a second heart attack or stroke generally should not have it stopped during a GI bleed, and that if it was interrupted, it be restarted on the day the endoscopist confirms bleeding has stopped. That recommendation is for clinicians managing the bleed, and it does not apply to aspirin taken without a prior heart attack or stroke. The point for patients is simpler: get evaluated quickly, bring a list of every medicine you take, and let the physicians caring for you decide what to hold and when to restart.

When black stools are an emergency

NIDDK advises seeking medical help right away for symptoms of acute or severe GI bleeding. Call 911 or go to the nearest emergency department if black, tarry stools come with any of the following:

• Dizziness, lightheadedness, or fainting
• A fast heartbeat or shortness of breath
• Confusion, pale skin, cold hands and feet, or sweating, which NIDDK lists as signs of shock
• Vomiting blood or material that looks like coffee grounds
• Large amounts of red or maroon blood from the rectum
• Severe abdominal pain
• Known cirrhosis or liver disease

Without those symptoms, black, tarry stools that are not explained by iron or bismuth still need same-day medical attention. MedlinePlus advises contacting a provider right away for changes in stool color. This is not a symptom to bring up at your next routine visit, and it is not something to manage at home. A gastroenterology office is the right place for the follow-up, not the first call for active bleeding.

How upper GI bleeding is evaluated

Much of the first part of care for an upper GI bleed happens in an emergency department or hospital. The ACG guideline notes that nearly 80% of people who come to an emergency department for upper GI bleeding are admitted, and that GI bleeding is the most common digestive diagnosis requiring hospitalization in the United States.

Risk assessment

Emergency clinicians check vital signs, blood counts, and other lab work, and many use a scoring tool called the Glasgow-Blatchford score. The ACG guideline suggests that people classified as very low risk, such as a score of 0 to 1, may be sent home with outpatient follow-up rather than admitted. It also stresses that this decision has to account for age, other health conditions, support at home, and access to care after discharge. A person sent home on that basis still needs the outpatient follow-up, and that is often where a gastroenterology practice comes in.

History and medicines

NIDDK and MedlinePlus describe the same questions: when the black stools started, whether every stool is that way, other symptoms such as vomiting blood, pain, or weight loss, and every medicine you take, including aspirin, ibuprofen, naproxen, blood thinners, iron, and bismuth.

Upper endoscopy

An upper endoscopy, or EGD, is the main test. A thin, flexible tube with a camera lets a gastroenterologist look at the esophagus, stomach, and duodenum. NIDDK notes that doctors can often both find and treat the bleeding during the same procedure, using injected medicines, heat, clips, bands, or a spray. For people admitted to the hospital, the ACG guideline suggests endoscopy within 24 hours of arrival. Biopsies taken during the procedure can check for H. pylori and look for other causes.

When the upper endoscopy is normal

Sometimes the source is not found on the first look. NIDDK describes capsule endoscopy, a swallowed camera that photographs the small intestine, along with longer scopes, colonoscopy, and CT imaging as next steps to find bleeding farther down.

Treatment and recovery after black stools

Treatment depends on the cause. For bleeding ulcers, the ACG guideline recommends endoscopic treatment for ulcers that are actively bleeding or show a visible vessel, followed by acid-suppressing medicine, a proton pump inhibitor, at a high dose for the first few days and then twice daily for about two weeks in higher-risk patients. The specific dose and length are decisions for the physicians treating you.

After a bleed, the outpatient work usually includes:

• Treating the cause. If H. pylori was found, treating it and confirming it is gone. If an NSAID was involved, reviewing whether it can be avoided. Our peptic ulcers and H. pylori page explains both.
• Checking for anemia. Blood loss can lower iron stores. Our page on iron deficiency anemia explains how it is evaluated. Iron pills, if prescribed, will darken the stool, so ask what to watch for.
• Reviewing medicines. Deciding with your prescribing physicians when and how to restart blood thinners or aspirin.
• Long-term acid suppression, where needed. Some people need to stay on a proton pump inhibitor, and our guide to long term PPI use covers what is known about that.
• Follow-up endoscopy, in some cases. Depending on what the first procedure found, your gastroenterologist may recommend a repeat look, and will explain why.

If black stools come back after treatment, the guidance is the same as the first time: same-day care, or 911 with any of the emergency signs above.

Preparing for a follow-up visit about black stools

If you were seen in an emergency department or hospital, or were told to follow up with a gastroenterologist, the visit goes further when you bring:

• Discharge papers, endoscopy reports, biopsy results, and recent blood counts, or the name of the hospital where you were seen
• A list of every medicine and supplement you take, including aspirin, ibuprofen, naproxen, blood thinners, iron, and bismuth
• When the black stools started, how many there were, and whether they have stopped
• Other symptoms, such as stomach pain, heartburn, vomiting, fatigue, or weight loss
• Any history of ulcers, liver disease, or heavy alcohol use

Our page on what to expect at your first gastroenterologist visit covers the rest, and when to see a gastroenterologist explains how other digestive symptoms are triaged.

Follow-up care for black stools at GC of NoVA

Gastroenterology Center of Northern Virginia sees adults across Arlington, Annandale, and the surrounding communities who have had black stools or an upper GI bleed and need to find and treat the cause. Our five gastroenterologists review what happened, what any earlier testing showed, and every medicine involved, and work with your other physicians on blood thinners and aspirin. Upper endoscopies are performed at VHC Health, Inova Fairfax Hospital, and the Woodburn Endoscopy Center.

We see patients at our Arlington office at 1715 N George Mason Drive, adjacent to VHC Health, and our Annandale office at 3299 Woodburn Road in the Woodburn Medical complex. To schedule a follow-up visit, call Arlington at (703) 522-7476 or Annandale at (703) 560-6106, or learn more at gcofnova.com. For black stools with dizziness, fainting, a racing heart, or vomiting blood, call 911 instead.

This article is for general education and is not medical advice. Talk with a qualified gastroenterologist about your symptoms, diagnosis, and treatment options.