What is bacterial overgrowth in the small intestine?

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What is bacterial overgrowth in the small intestine?

In around two thirds of those affected by irritable bowel syndrome, the cause is bacterial overgrowth in the small intestine, SIBO for short. 

Here you can find out more about the causes, symptoms and treatment of bacterial overgrowth: 


If you suffer from SIBO (Small Intestinal Bacterial Overgrowth = bacterial overgrowth in the small intestine), then bacteria from your large intestine have migrated into the small intestine and are making themselves comfortable there. While the large intestine is teeming with various bacteria, the small intestine is normally hardly populated with intestinal bacteria. The misaligned intestinal bacteria mess things up here. They metabolize carbohydrates prematurely and thereby produce gases (primarily hydrogen and methane) that cannot escape. These gases may also be the reason for your symptoms, such as the often typical bloated stomach.


The fact that irritable bowel symptoms in most cases are caused by bacterial overgrowth in the small intestine has been confirmed by a large number of scientific studies.                                          

The most common symptoms of SIBO:

  • abdominal cramps in the upper abdomen
  • Bloated stomach
  • bloating
  • diarrhea
  • constipation
  • Alternating diarrhea/constipation
  • Eructation

Causes of small intestinal bacterial overgrowth (SIBO)

The causes of bacterial overgrowth in the small intestine have not yet been fully elucidated. The most common causes of SIBO are food poisoning, long-term stress, and drug therapies such as prolonged, or frequent, antibiotic treatments. 


Other possible causes include poor nutrition, a change in the intestinal flora and operations with secondary adhesions 

in the gut. Certain diseases such as Crohn's disease or celiac disease and other chronic inflammations in the small intestine can also increase the risk of bacterial overgrowth in the small intestine.                                                             

How can I test bacterial overgrowth?

You can easily test bacterial overgrowth in the small intestine with a SIBO breath test at home.


After preparing the diet, you feed the colonized intestinal bacteria with a sugar solution (e.g. lactulose). The bacteria then begin to metabolize the carbohydrates in the small intestine. They mainly produce hydrogen and methane. They release these gases into your blood. From there they get into the air you breathe via the lungs. With the SIBO breath test, you collect these gases.


You blow in a certain rhythm in several glass tubes, which are later evaluated in the laboratory. If the time curve in the result report shows a premature increase in initial hydrogen or methane or both, there is a high probability of small intestinal bacterial overgrowth (SIBO).


Treat Sibo, how does it work?

Once you have finally found out more about the condition in your intestines with the Sibo breath test, you can now use your irritable bowel syndrome therapy in a much more targeted manner.


A SIBO treatment consists of several elements:


Herbal or synthetic antibiotics, certain dietary supplements and a Sibo nutrition plan will help you to keep reducing the colonized intestinal bacteria.


You should always discuss which therapy is the right one for you for bacterial miscolonization in the small intestine with a doctor or naturopath: in one or other therapists who are familiar with the treatment of bacterial miscolonization in the small intestine.


Find out now whether bacterial overgrowth in the small intestine is the cause of your irritable bowel symptoms: