Melena (Black Stool)

What is melena (black stool)?

“Melena” is the medical term for the black, tarry stool that comes from bleeding in your upper gastrointestinal (GI) tract. Black stool is a sign of older blood in your stool. The blood turns black and tarry while traveling through your GI tract from higher up, where it started — usually in your stomach or upper small intestine. Digestive chemicals interact with the blood during its journey, changing its color and texture.

What is the difference between melena and black stool?

Healthcare providers diagnose melena when they’ve confirmed that the color of your poop is, in fact, from internal bleeding. Black stool is often a sign of gastrointestinal bleeding, but not always. Certain medications, supplements and foods may also turn your poop black. In that case, it’s not called melena.

What is the difference between melena and GI bleeding?

Melena is a sign of bleeding in your upper GI tract. But not all gastrointestinal bleeding turns black. If you’re bleeding from lower down, like in your large intestine, it’s more likely to come out looking red. Lower GI bleeding is fresher and has less distance to travel before it comes out in your poop.

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:

• Peptic ulcer disease (a bleeding ulcer in your stomach or duodenum).
• Severe inflammation (gastritis or esophagitis).
• Erosion of your stomach lining (acute hemorrhagic erosive gastropathy).
• Trauma or gastrointestinal perforation (a tear in the lining of your GI tract).
• Swollen and ruptured veins (varices) in your esophagus or stomach.
• A tear in your esophagus caused by violent vomiting.
• Cancer in your stomach, esophagus or pancreas.
• Viral hemorrhagic fevers, such as Ebola.

What are other causes of black stool (besides melena)?

Certain medicines, supplements and foods may stain your stool black, including:

• Iron supplements.
• Bismuth subsalicylate (Pepto Bismol®).
• Activated charcoal.
• Blood sausage or large amounts of dark foods, such as black licorice or blueberries.

How do I know if my black stool is melena?

A healthcare provider can test your stool to determine if it has blood in it. A provider will also ask you questions about your health history, your symptoms and the nature of your poop. They might ask:

What does it look like?

Classic melena is jet black with a tarry, sticky consistency. This can be one way of distinguishing melena from stained-black stool. However, some causes of upper GI bleeding and melena can also cause diarrhea, making it wetter. A small amount of bleeding may look more dark brown than black.

What does it smell like?

Melena is known for its particularly strong, offensive odor. The smell is a byproduct of blood being broken down and digested in your GI tract. The longer it’s traveled, the darker and smellier it is. You won’t notice the same distinctive smell with stained-black poop, which doesn’t have blood in it.

What other symptoms do you have with melena?

Other symptoms can be a clue to what’s causing the bleeding or where it’s coming from. For example:

Abdominal pain may signal a stomach condition, like an ulcer, gastritis or gastropathy. Chest pain may be from your esophagus. Pancreatic conditions can cause either upper abdominal pain or back pain. If you feel no pain, you might have a silent ulcer, a tumor or a ruptured blood vessel in your GI tract.

Some people with upper GI bleeding also vomit blood. Blood in your vomit, and what it looks like, can be other clues. Fresh, red blood in your vomit suggests an active bleed in your stomach or esophagus. Dark brown, textured blood that looks like coffee grounds is older and suggests the bleeding has stopped.

What medical tests will I have to diagnose melena?

If your healthcare provider suspects you have melena, they’ll start by testing your stool. A fecal occult blood test can determine if there’s blood in your stool that you can’t clearly see. But diagnosing melena is just the beginning. Your provider will then need to diagnose and address the cause of your bleeding.

Tests may include:

• Blood tests. A comprehensive metabolic panel can give your provider basic information about your overall health and how much blood you’ve lost, and then suggest possible causes.
• Imaging tests. A CT scan or CT angiogram may help locate the source of the bleeding.
• Upper endoscopy. An upper endoscopy (EGD test) looks inside your upper GI tract to find and possibly fix the bleeding. A healthcare provider passes a thin tube with a camera attached to it down your throat and into your stomach and duodenum. They can take tissue samples if necessary and perform certain procedures through the endoscope to stop an active bleed.

What is the treatment for melena (black stool)?

Treatment for melena involves:

• Treating your blood loss.
• Stopping the bleeding.
• Treating the cause of the bleeding.

Your healthcare provider will assess your overall condition to determine the treatment you need. Depending on how much blood you’ve lost, you may need IV fluids or a blood transfusion to restore your blood volume. Some people may even need intensive care before further testing or treatment.

Your provider can often stop active bleeding and prevent new bleeding with endoscopic therapies. During an upper endoscopy, they might seal the wound with electrocautery or by injecting medication into it. Sometimes, they place a clip or band on the blood vessel. Sometimes, stitches are needed.

Acid-blocking medications called proton pump inhibitors (PPIs) are often prescribed for ulcers, inflammation or erosion in your gastrointestinal lining. They promote healing and help protect the tissues from chemical damage. Some of the causes of melena will need more comprehensive treatment.

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. The blood that turns your stool black has traveled some distance. By the time you notice melena, that blood may be a few days old. But you may still be bleeding and losing blood.

When should I seek urgent care?

Go to urgent care or an ER if you have symptoms of severe bleeding, such as:

• Vomiting blood or vomit that looks like coffee grounds.
• Feeling dizzy, weak or lightheaded.
• Heart palpitations and shortness of breath.
• Several days of melena or blood in your stool.

A note from Cleveland Clinic

Black stool (melena) is an odd thing to find, and you might not associate it with bleeding at first. Learning that there’s actually blood in your stool might be upsetting, and rightly so. While red blood is more recognizable, it also has more benign causes. The black blood that causes melena, however, comes from deep inside your body. Internal bleeding requires attention and care from a skilled healthcare provider.