What Does H. Pylori Poop Look Like? Constipation, Diarrhea, and Black stool.

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Can H. pylori change the look of your poop?

H. pylori is an infection of the stomach (often attached to the lining cells at the last third of the stomach (pylorus)) (1).

H. pylori is a prevalent disease. Approximately two-thirds of the world population is infected with h. pylori (2).

The prevalence is higher in developing countries than in developed ones.

For example, H. pylori affect about 38% of the population in the USA and more than 90% of the Nigerian people (3)

how common is h pylori

In most cases, H. pylori infection doesn’t change the look of your poop. However, when h. pylori cause a bleeding stomach ulcer; your poop may turn black or coffee-ground in color. 

Less commonly, H. pylori may result in changes in bowel movements (constipation or diarrhea). The link between h. pylori and constipation or diarrhea are discussed in detail later in this article.

When you have an H. pylori infection, you cannot rely on the look of your poop to diagnose it. Stool changes with H. pylori seldom occur. Moreover, the research is not well established because of the link between H. pylori and bowel habit changes (constipation and diarrhea).

The most significant H. pylori-related disease is chronic gastritis and Peptic ulcer disease. These diseases often present with upper-middle (epigastric) pain in your stomach and indigestion (dyspepsia). Poop changes are not typical with gastritis, but they can happen.

Learn more: 6 possible causes of constipation with gastritis.

What do H. pylori look like in stool?

what does h. pylori look like in stool?

H. pylori are microscopic organisms; it is impossible to see them in the stool with your naked eyes. However, H. pylori pass in the stool, and your doctor may order a stool test to diagnose H. pylori infection.

H. pylori stool antigen is widely used to detect active infection. And it is the only way we use a stool to find H. pylori. 

Under the electron microscope, H. pylori look like a rod with multiple tails (flagella) that helps the organism move. Moreover, conventional stool analysis and light microscopy examination cannot detect H. pylori in your stool.

Can H. pylori cause black or coffee ground stool?

Black, coffee ground, or tar-like poop may indicate bleeding from the upper part of your digestive tract (the esophagus, stomach, duodenum, and the early part of your small intestines.

H. pylori-infected individuals have a 10-20% lifetime risk of peptic ulcer disease (4). but bleeding from such ulcers is infrequent 

So, the incidence of h. pylori-induced black stool is rare but dangerous. The presence of black tarry stool can be a symptom of bleeding H. pylori-induced ulcers.

This is a medical emergency; please call your doctor now or head to the ER t get medical help.

The link between H. pylori infection and constipation?

In a 2018 study, treatment of h. pylori in patients with constipation resulted in some improvement in constipation (5).

Also, H. pylori is linked to Parkinson’s disease in the research (6). Parkinson’s disease is known to cause severe chronic constipation.

These pieces of evidence may indicate that h. pylori may play a role in constipation. However, the evidence is still weak, and constipation with H. pylori is not a frequent complaint.

If you have constipation with H. pylori, consult your doctor about the possible causes and best treatment.

Does H. pylori cause diarrhea?

Diarrhea is not a reported symptom of h. pylori infection. However, some research found a link between H. pylori, atrophic gastritis, and the disturbance of gut microbiota. 

Both atrophic gastritis (decreased gastric acid production) and the disruption of gut microbiota can lead to diarrhea.

However, the research evidence is conflicting. And no evidence that the frequency of diarrhea is higher among H. pylori individuals than in the general population.

Also, you should note that diarrhea with H. pylori may result from antibiotics, anti-acid medications that are used to treat h. pylori. With diarrhea, your poop may look yellow and loose or watery. However, it is not a specific sign of H. pylori.

To give a picture, Here is a summary of some interesting studies about the topic:

  • The use of probiotics (which restore beneficial gut microbiota decreased the incidence of diarrhea with H. pylori treatment (7).
  • H. pylori infection may play a protective role against bacterial diarrhea in children (8).
  • On the other hand, researchers have found a link between H. pylori infection and chronic diarrhea in children (9).
  • Also, another Peruvian study found that acute H. pylori infection is followed by an increase in diarrhea among children (10).

We still need well-designed large-scale clinical studies to understand the link between H. pylori and diarrhea. 

If you have your poop looking like diarrhea with H. pylori, discuss the issue with your doctor to determine the cause and the best treatment.


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