Small intestinal bacterial overgrowth (SIBO) occurs when there’s an increase in the bacterial population in the small intestine. It can cause digestive symptoms, including bloating and pain.

Small intestinal bacterial overgrowth (SIBO) is a serious condition affecting the small intestine. It occurs when there is an increase in the bacterial population in the small intestine. These bacteria may be found in small amounts in other parts of the gut and eliminated regularly. This causes pain and diarrhea. It can also lead to malnutrition, as the bacteria start to use up the body’s nutrients.

Read on to learn more about SIBO.

SIBO symptoms mainly affect the gut. Symptoms may include:

You may also experience unexpected weight loss.

SIBO is not yet well understood. It can occur when:

  • your small bowel has anatomic abnormalities
  • the pH changes in your small bowel
  • your immune system is not working properly
  • the muscular activity of the small intestine malfunctions, which means that food and bacteria are not removed from the organ

SIBO is associated with various conditions, such as:

Read more: What’s causing this abdominal pain and diarrhea?

Having a chronic condition or surgery that affects the gastrointestinal (GI) tract can put you at risk of SIBO. Certain diseases and chronic conditions can also increase your risk, including:

See a doctor if you have symptoms of SIBO. Your doctor will ask about your symptoms and medical history. They’ll also do a physical examination, which may include palpating, or gently feeling, your abdomen. They may also order blood, fecal, or other tests.

Breath test

A breath test is a common test for diagnosing SIBO. Excess bacteria in the small intestine can lead to the release of the gases hydrogen and methane, which can be identified through a breath test. This test is noninvasive and can be performed at home or in a doctor’s office.

You’ll need to fast overnight before having a breath test. During the test, you’ll breathe into a tube. You’ll then drink a special sweet drink provided by your doctor. You’ll breathe into a series of additional tubes at regular intervals for 2 to 3 hours after consuming the drink.

Further testing

If the breath test is not conclusive or SIBO treatments are not working, your doctor may need to get a sample of the fluid from your small bowel to see what bacteria are growing there.

SIBO can be treated with a combination of antibiotics and diet changes.


First, you need to get the bacteria under control. This is usually done with antibiotics, such as:

You may need replacement of fluids, vitamins or minerals in cases of dehydration and malabsorption.

Antibiotics may decrease the number of bacteria in the small intestine, but they will not address the underlying issue that caused the problem in the first place. If a doctor determines that your SIBO is due to an underlying condition, you’ll also need to begin treatment for that condition. Diet changes may also help.

Diet and SIBO

There’s no evidence to prove that a certain diet causes SIBO, but many people with SIBO have found relief after following a special diet. Talk with a doctor before making any changes to your diet.

You may only need to make small changes, such as:

  • Eat a balanced, nutritious diet.
  • Eat smaller meals more frequently to avoid having too much food sitting in your stomach.
  • Avoid gluten products if you have celiac disease.

Your doctor may also recommend trying an elemental diet. This diet replaces food and drinks with certain liquid formulas for a specified amount of time. More research is needed, however. Work with your doctor before starting this diet, and follow their instructions.

Can probiotics be used to treat SIBO?

Taking probiotics could help the bacteria in your gut return to normal. A 2010 study found that probiotic treatment could be more effective at treating SIBO than antibiotics. However, a review from 2016 found that evidence for the effects of probiotics in treating SIBO was inconclusive. Your best option is to follow your doctor’s advice.

If SIBO is left untreated, it may lead to malnutrition and dehydration. It’s important to receive treatment right away to avoid these complications.

SIBO usually occurs because of an underlying condition. If you have a chronic condition, such as Crohn’s disease or celiac disease, work with a doctor to develop a long-term treatment plan.

SIBO is treatable, but it may recur. It can also lead to dehydration and malnutrition when it’s left untreated. Contact your doctor if you suspect you have SIBO so you can start treatment right away.