What is Melena? Identifying Black, Foul-Smelling, Tarry Stools

What Is Melena? Identifying Black and Tarry (Melena) Stools

Melena is the medical term used to describe black and tarry stools that often have a strong, foul odor. This appearance usually happens when blood is present in the stool and has been partially digested as it moves through the gastrointestinal (GI) tract. Because melena can be a sign of internal bleeding, it is important to understand what it means, what causes it, and when to seek medical care.

This article explains melena in clear, everyday language, without unnecessary alarm—but also without minimizing its importance.

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What Does "Black and Tarry (Melena)" Mean?

Under normal circumstances, stool color ranges from light to dark brown. Black and tarry stools (melena) are different in several ways:

• Color: Jet black or very dark brown
• Texture: Sticky, thick, and tar-like
• Smell: Strong, unpleasant, and unusually foul

This combination happens because blood has been exposed to stomach acid and digestive enzymes, which darken it and change its texture and odor.

Melena usually indicates bleeding in the upper part of the digestive system, such as the esophagus, stomach, or upper small intestine.

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Why Does Blood Turn Stool Black?

When bleeding occurs high in the GI tract, the blood has time to be digested. As hemoglobin breaks down, it forms compounds that make the stool appear black and sticky.

This is different from bright red blood in stool, which often comes from lower areas like the colon, rectum, or anus.

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Common Causes of Black and Tarry (Melena) Stools

Melena is not a condition itself—it is a symptom. Some of the more common causes include:

Upper Gastrointestinal Bleeding

• Stomach ulcers
• Duodenal ulcers
• Gastritis (stomach lining inflammation)
• Esophagitis (esophagus inflammation)

Esophageal Conditions

• Esophageal varices (enlarged veins, often related to liver disease)
• Tears in the esophagus from severe vomiting

Medications and Substances

• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin
• Blood thinners
• Steroids, when combined with NSAIDs
• Excessive alcohol use

Infections or Serious Conditions

• Helicobacter pylori (H. pylori) infection
• Stomach or esophageal cancer
• Severe physical stress (major illness, burns, or trauma)

Some non-bleeding causes can darken stool but do not cause melena, such as iron supplements or certain foods. These usually do not produce the tarry texture or foul smell typical of melena.

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Symptoms That May Occur Alongside Melena

Black and tarry stools may appear alone or with other symptoms, depending on the cause and severity of bleeding. These can include:

• Fatigue or weakness
• Dizziness or lightheadedness
• Shortness of breath
• Abdominal pain or discomfort
• Nausea or vomiting
• Vomiting blood or material that looks like coffee grounds
• Pale skin

These symptoms may indicate significant blood loss and should not be ignored.

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When Is Melena Considered Serious?

Melena is often considered medically significant, especially when:

• It appears suddenly
• It happens more than once
• It is accompanied by weakness, dizziness, or fainting
• There is a history of ulcers, liver disease, or blood-thinning medication use

While not every case is life-threatening, black and tarry (melena) stools should always be taken seriously. Internal bleeding can worsen quietly over time.

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How Doctors Evaluate Black and Tarry (Melena) Stools

If you speak to a doctor about melena, they may recommend:

• Medical history review, including medications and alcohol use
• Physical examination
• Blood tests to check for anemia or infection
• Stool testing for blood
• Endoscopy, which allows direct viewing of the esophagus and stomach
• Imaging studies, if needed

The goal is to find the source of bleeding and stop it as quickly and safely as possible.

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Can Diet or Supplements Cause Black Stool?

Yes—but with important differences.

Certain things can darken stool without bleeding, such as:

• Iron supplements
• Bismuth-containing medications
• Very dark foods (e.g., black licorice, blueberries)

However, these stools are usually:

• Not tarry
• Not foul-smelling
• Not associated with weakness or dizziness

If there is any doubt, it is safer to assume melena until proven otherwise by a healthcare professional.

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What Should You Do If You Notice Black and Tarry (Melena) Stools?

If you notice stool that is black, sticky, and foul-smelling:

• Do not ignore it
• Do not stop prescribed medications without guidance
• Seek medical advice promptly

If you're experiencing symptoms and want to better understand what might be causing them before speaking with a healthcare provider, you can use a free Blood in stool symptom checker to receive personalized guidance on the appropriate level of care you may need.

This type of tool is not a diagnosis, but it can help you prepare for a more informed conversation with a doctor.

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Treatment Options for Melena

Treatment depends entirely on the cause and severity of bleeding. Possible treatments include:

• Medications to reduce stomach acid
• Antibiotics for H. pylori infection
• Stopping or adjusting medications that irritate the stomach
• Endoscopic procedures to stop active bleeding
• Blood transfusions in severe cases
• Surgery, in rare but serious situations

Early treatment often leads to better outcomes and fewer complications.

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Red Flags That Require Urgent Medical Attention

Seek immediate medical care if melena occurs with:

• Fainting or collapse
• Rapid heartbeat
• Severe abdominal pain
• Vomiting blood
• Confusion or extreme weakness

These may signal significant internal bleeding, which can become life-threatening if not treated quickly.

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The Importance of Speaking to a Doctor

Even if you feel "mostly okay," black and tarry (melena) stools are not normal. They are a sign your body is trying to alert you to something happening internally.

If there is any concern that your symptoms could be serious or life-threatening, you should speak to a doctor as soon as possible. Early evaluation can prevent complications and, in many cases, save lives.

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Key Takeaways

• Melena refers to black, tarry, foul-smelling stools caused by digested blood.
• It usually points to bleeding in the upper digestive tract.
• Not all black stool is melena, but melena should always be evaluated.
• Symptoms like dizziness, weakness, or vomiting blood increase urgency.
• Tools like a free Blood in stool symptom checker can help guide next steps.
• Always speak to a doctor about symptoms that may be serious.

Understanding melena empowers you to act wisely—not fearfully—and to get the care you need at the right time.