Hematochezia vs. Melena: Causes, Diagnosis, and Treatments

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Hematochezia vs. melenaHematochezia vs. melena. Both are medical conditions linked to blood in stool, but what are the differences? Is one simply pooping blood along with stools, while the other is caused by rectal bleeding? In this article, we will compare and contrast hematochezia and melena, examining hematochezia causes and melena causes, as well as how each condition is diagnosed and treated.

Melena refers to the passing of dark, tar-like blood in your stool. The deep burgundy and sometimes black color indicates bleeding in the upper gastrointestinal (GI) tract, which includes the esophagus, stomach, and duodenum.

Hematochezia signals bleeding in the lower GI tract—anus, rectum, large intestine, and small intestine. Blood resulting from this condition is typically bright red in color.

Difference between Hematochezia and Melena

What is the difference between melena and hematochezia? As noted, both demonstrate intestinal bleeding. Both should also be checked out by a doctor as soon as possible. The most notable difference between hematochezia and melena is the site of the bleeding. The below table provides a quick guide to the important distinctions.



Definition Passage of fresh blood in stool Passage of black, tar-like stools
Causes Bleeding in the lower gastrointestinal tract (from lower small intestine to anus). Bleeding in the upper gastrointestinal tract (stomach, esophagus, upper small intestine).
Diagnosis Colonoscopy Upper GI endoscopy
Treatment Treatment typically involves treating the root cause of the bleeding (hemorrhoids, diverticulosis, colorectal cancer, etc.) Treatment typically involves treating the root cause of the bleeding (peptic ulcer, cirrhosis, anti-inflammatory drugs, etc.)

Hematochezia vs. Melena Causes

The causes of hematochezia and melena are entirely separate, despite having similar end results.


The main cause of hematochezia is bleeding anywhere from your lower small intestine to your anus. The blood you find in your stool will be new, and may be hard to spot initially. When it appears, it tends to be a fresh, red color, as it has not been in your digestive tract for long.

What causes the bleeding itself? The factors are varied. Rectal fissures and hemorrhoids are the primary causes, but bleeding may also originate from the lower intestines. Other causes can include:

  • Diverticulosis
  • Inflammatory bowel disease
  • Ulcerative colitis
  • Necrotizing enterocolitis (newborns and young infants only)
  • Colorectal cancer

The stool, however, may appear in different colors. It could be dark due to the infiltration of blood into the stool or coating the stool, or it could be a lighter color of red or even pink.


Melena is blood in the stool from the upper gut area. Because the blood has traveled further down the digestion tract and spent more time in the system, the blood and the stool will appear dark. Exposure to gut bacteria, air, and digestive enzymes breaks down the blood cells, which causes them to turn maroon or black in color.

What causes the bleeding in the first place can be a range of medical issues, most commonly ulcers both gastric and peptic. Other issues that can cause melena are:

  • Trauma to the stomach
  • Blood vessel disorders
  • Ingested blood from nosebleeds or trauma to the mouth
  • Bacterial infections
  • Radiation therapy
  • Intestinal parasites
  • Incorrect blood-type transfusions
  • Ingestion of a foreign object
  • Gastroesophageal reflux disease
  • Thrombocytopenia (an inability of cells to clot)
  • Mallory-Weiss tear (vomiting causing an esophageal tear)
  • Liver cirrhosis
  • Arsenic poisoning
  • Oral drug overdose
  • Stomach cancer

It should be noted that Crohn’s disease can cause both melena and hematochezia.

Hematochezia vs. Melena Diagnosis

If you have found blood in your feces but are unsure of the color, how does your doctor confirm a diagnosis of either hematochezia or melena?

After he or she goes through your recent medical history (in order to either rule out or rule in certain influences), the next step is a round of physical testing starting with a general physical exam. If an anal fissure is present, for example, it can be spotted right away by a trained doctor. The cause of your melena will be quickly diagnosed and treated.

If no obvious signs of blood in the stool are found, more invasive medical examinations are required. The most common of the tests are an upper endoscopy and a colonoscopy.

Upper Endoscopy

An upper endoscopy utilizes a small tube that contains a light and a camera, which is inserted down your throat and into the digestive area. The camera is hooked up to a color monitor, so doctors can get a good look at your stomach, esophagus, and the upper portion of your small intestine.

From there, the doctor should be able to determine whether melena is causing the blood in your stool, and if so, what is causing the bleeding.


This diagnostic procedure is similar to the upper endoscopy, but may require more work on the part of the patient. Before a colonoscopy is performed, your doctor may put you on a small diet for a few days that would require less fiber, more clear liquids, and laxatives.

The purpose is to clear out the colon and entire intestinal tract as much as possible. You will be medicated, so that you can relax as you lie on your left side and the colonoscope is inserted into your rectum.

A colonoscope is a slim tube equipped with a camera and light, allowing the doctor a full view of the lower intestinal tract. Starting with the rectum and moving up into the lower intestines, the doctor will survey any possible causes of bleeding.

Both colonscopes and endoscopes are equipped to take samples for further lab testing if necessary.

Beyond these two main treatments, other tests may include:

  • Nasogastric lavage: For this test, stomach contents are removed via a tube inserted into the stomach. They are then checked for signs of blood.
  • Enteroscopy: This procedure used to examine the small intestine will have you swallow a capsule with a tiny camera inside that transmits images as it passes through the digestive tract.
  • Barium X-ray: The method uses a contrast material called barium to highlight the digestive tract on an X-ray. The barium may either be swallowed or inserted rectally.
  • Radionuclide scanning: In this test, small amounts of radioactive material are injected into a vein. Doctors then use a special camera to track the blood flow in the digestive tract to detect where bleeding is occurring.
  • Angiography: Comparable to a radionuclide scan, a special dye is injected into a vein that makes blood vessels visible on an X-ray or computerized tomography (CT) scan. The procedure detects bleeding as dye leaks out of blood vessels at the area of bleeding.
  • Laparotomy: If all other tests fail, this technique may be used to track the bleeding by opening up the abdomen for a direct examination.

Hematochezia vs. Melena Treatments

Generally, gastrointestinal bleeding is caused by an underlying medical issue. When that issue is treated, the bleeding should go away. The treatment processes for melena and hematochezia are similar in that nature.

Treatment may become complicated when there is excessive blood. In such cases, a hospital stay and surgery may be required. Root causes like ulcers may be treated without surgery. However, most cancers involve extensive treatment, including radiation therapy, chemotherapy, and/or surgery.


Treatment for hematochezia will depend on the source. Diverticulosis, the development of small pouches in the colon walls, is a common cause. If it is mild, treatment may include a course of antibiotics and a liquid diet until your bowels heal. A more aggressive case will require surgery to repair the damage.

Inflammatory bowel disease and ulcerative colitis have similar treatment programs consisting of anti-inflammatories, immune suppressors, and antibiotics. Anti-diarrhea medications and pain medications may also be provided to help a patient through the symptoms.


Many causes behind melena can be treated by medications quickly and efficiently. Bacterial infections and parasites, for example, can often be cleared with a simple antibiotic. Gastroesophageal reflux disease (GERD) can be managed with either over-the-counter medication or prescription drugs depending on the severity.

For other frequent causes like stomach cancer, Mallory-Weiss tear, and liver cirrhosis, treatment may consist of a combination of medications and surgical procedures. Stomach cancer may require multiple rounds of radiation and chemotherapy. Cirrhosis can require medications, dietary changes, and in advanced cases, a liver transplant.

Stomach ulcers can usually be treated with medications but in severe cases may require surgery.

Hematochezia vs. Melena: Get Checked Out

Whether your problem is hematochezia or melena, blood in your stool is not to be ignored. More often than not, it is a sign of a more serious medical condition that needs to be examined by a doctor as soon as possible.

While some underlying health conditions are not necessarily severe, left untreated, they can become life-threatening. If you have blood in your stool, seek medical treatment and get on the road to recovery right away.

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