What Is It, Causes, Symptoms, Bleeding, Treatment, and More

Author: Jennifer Cheung, RN

Editors: Antonella Melani, MD, Lisa Miklush, PhD, RN, CNS, Ahaana Singh

Illustrator: Jillian Dunbar

What is melena?

Melena refers to black stools that occur as a result of gastrointestinal bleeding. This bleeding typically originates from the upper gastrointestinal (GI) tract, which includes the mouth, esophagus, stomach, and the first part of the small intestine. In some cases, bleeding in the ascending colon of the large intestine, which is located in the lower GI tract, can also result in melena.

Melena should not be confused with hematochezia, which refers to fresh blood in the stools that leads to maroon or red-colored stools. This blood typically comes from the lower GI tract, most often from rectal bleeding, such as hemorrhoids.

What causes melena?

Melena often results from damage to the upper GI tract lining, swollen blood vessels, or bleeding disorders.

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What symptoms are associated with melena?

Melena appears as black, tar-like, sticky stools. The black color is caused by enzymes breaking down and digesting the blood as it moves through the GI tract. This color is often accompanied by a strong, foul odor. 

Associated symptoms that may be seen with melena vary depending on the amount of blood loss and the source of bleeding. 

How do you diagnose melena?

Diagnosis begins by identifying the sources of bleeding in order to determine and treat the underlying cause. 

  • Clinical evaluation

    • Medical history review 

      • Identify related causes, such as chronic NSAID use. 

  • Procedural diagnosis

    • Nasogastric lavage (also known as the pumping of stomach contents) can be used to determine the severity of blood loss. 

    • Upper endoscopy (a minimally invasive procedure used to look inside the body) will often be performed to determine the exact source of bleeding.

How do you treat melena?

  • Medications 

  • Procedures

    • If necessary, the bleeding can be controlled through a combination of endoscopic therapies

      • Injection therapy involves the injection of medication directly into the source of bleeding to encourage coagulation (blood clotting). 

      • Thermal techniques apply heat probes to cauterize the bleeding. 

      • Mechanical techniques apply pressure, using devices like clips or rubber band ligation.

    • Angiographic embolization may be performed, in which medication or coils are placed onto a guided catheter to block blood flow at the location of bleeding. 

    • Surgical therapies can also be used to stitch up ulcers or lacerations. 

    • Severe cases may need blood transfusions.

Frequently Asked Questions

Is melena a sign of active bleeding?

If melena is accompanied by symptoms of shock, it can be a sign of active bleeding. In such cases, it is considered a medical emergency and it is important to seek medical attention immediately. On the other hand, cases with no apparent symptoms of shock should seek medical attention if the melena continues beyond 5 to 7 days. 

How long does melena last?

Depending on the amount of blood loss and the individual’s gastrointestinal motility, melena may continue up to 5 days after the bleeding has stopped.

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Related links

Clinical Reasoning GI Bleeding
High Yield Gastrointestinal Bleeding
Peptic ulcer disease
Portal hypertension
Gastric cancer

Resources for research and reference

Feldman, M., Friedman, L. S., & Brandt, L. J. (2015). Sleisenger and Fordtran’s Gastrointestinal and Liver Disease Pathophysiology Diagnosis Management (10 edition). Philadelphia, PA: Elsevier.

Goldman, L. & Schafer, A. I. (2016). Goldman-Cecil Medicine (25 edition). Philadelphia, PA: Elsevier.

Parrillo, J. E. & Dellinger, R. P. (2019). Critical Care Medicine Principles of Diagnosis and Management in the Adult (5 edition). Philadelphia, PA: Elsevier.

Walls, R. M., Hockberger, R. S., Gausche-Hill, M., Bakes, K., Baren, J. M., Erickson, T. B., Jagoda, A. S., Kaji, A. H., VanRooyen, M., & Zane, R. D. (2018). Rosen’s Emergency Medicine Concepts and Clinical Practice (9 edition). Philadelphia, PA: Elsevier.