SIBO Treatment: How to Get Rid of SIBO, From Breath Test to Lasting Relief

Bloating that builds through the day, gas, belly pain and loose stools can have many causes. One that gets a lot of attention online is small intestinal bacterial overgrowth, or SIBO. It is a real condition, but it is also easy to over-diagnose. SIBO treatment works best when it is based on proper testing and a search for the underlying cause. Gastroenterologists test for it and treat it following the American College of Gastroenterology (ACG) guideline.

What SIBO is

Your large intestine (colon) is home to enormous numbers of bacteria, while the small intestine normally has far fewer. In SIBO, too many bacteria grow in the small intestine and start fermenting food before your body has absorbed it. That fermentation makes gas and can irritate the bowel, and the ACG guideline lists the most common symptoms as:

• Bloating (the single most common symptom)
• Gas and belly swelling
• Belly pain or cramping
• Diarrhea

In more severe cases, SIBO can lead to weight loss, fatty stools and low levels of vitamin B12, vitamin D or iron. No single symptom proves SIBO, though, because the same complaints are common in irritable bowel syndrome (IBS), which is why testing matters.

Causes of SIBO

Stomach acid, digestive enzymes, bile and regular waves of muscle contraction normally keep small-bowel bacteria in check. The ACG notes that SIBO almost always happens because one of these defenses has broken down. One common cause is slow movement through the gut, since diabetes and scleroderma can damage the nerves or muscles of the bowel. Medicines that slow the gut, such as opioid pain medicines, can have a similar effect, and so can an underactive thyroid (hypothyroidism), which the ACG lists among the conditions linked to SIBO.

Prior abdominal surgery is another, including some stomach and weight-loss operations that create a loop where contents can sit. Removal of the ileocecal valve (the gate between the small and large intestine) can also play a part.

Structural problems such as pouches in the small bowel (small bowel diverticulosis) can also allow overgrowth, and so can Crohn’s disease, especially after surgery. Chronic pancreatitis and other conditions that get in the way of digestion raise the risk, as do immune problems. Older age is linked to a higher chance of SIBO as well. Acid-lowering medicines have been studied as a possible cause, but the ACG advises against breath testing people on these medicines who have no symptoms. If you take one, don’t stop it on your own; talk with your doctor instead.

How to get rid of SIBO: the steps doctors follow

There is no single SIBO protocol that fits everyone, but treatment that works tends to follow the same order. The American Gastroenterological Association (AGA) says care should focus on finding and correcting the underlying cause, fixing any nutrient shortfalls and using antibiotics. In practice, that usually looks like this:

1. Confirm it. A breath test, or sometimes a sample taken during upper endoscopy, shows whether SIBO is really there.
2. Treat the overgrowth. Your doctor picks an antibiotic plan based on your results, including whether methane is involved.
3. Ease symptoms with food. A short, lower-fermentation eating plan can calm bloating while treatment works.
4. Find the cause. Slow gut movement, past surgery or another condition often explains why bacteria built up.
5. Correct shortfalls. Low vitamin B12, vitamin D or iron are checked and treated when needed.
6. Follow up. If symptoms come back, your doctor looks again before deciding on another round.

Each of these steps is covered in more detail below.

How SIBO is diagnosed

The breath test

The most common test is a hydrogen and methane breath test. Human cells don’t make these gases, but bacteria do when they ferment sugar. So if gas shows up in your breath soon after you drink a sugar solution, it suggests bacteria are fermenting it early in the small intestine. The test is noninvasive and painless, and it usually goes like this:

1. Weeks before: You may be asked to avoid antibiotics for 4 weeks and to stop laxatives and gut-speeding medicines for at least a week, only if your doctor says it is safe.
2. The day before: You eat a simple diet that avoids fermentable foods, such as beans, whole grains and high-fiber foods.
3. The night before: You fast for 8 to 12 hours.
4. Test day: You breathe into a bag or tube to get a starting sample, then drink a measured sugar solution (glucose or lactulose). You give more breath samples at set times over the next couple of hours, without smoking and with only light activity.

What the results mean

The ACG uses the North American consensus criteria. Under them, a rise in hydrogen of at least 20 parts per million above your starting level within 90 minutes points to SIBO. A methane level of 10 parts per million or more at any point points to intestinal methanogen overgrowth (IMO) instead. Methane is made by organisms called archaea, not bacteria, and it is linked to constipation rather than diarrhea.

Breath tests are useful but not perfect, because they can miss SIBO or flag it when it isn’t there. The ACG also notes that home mail-in kits are harder to control.

Other tests

A sample of fluid from the small intestine, taken during an upper endoscopy, can be cultured for bacteria. This approach is more direct but more involved. Blood tests for vitamin and iron levels may be part of the workup too.

How SIBO treatment works

Antibiotics

The ACG suggests antibiotics for people with symptoms and confirmed SIBO, with the goal of reducing the overgrowth and relieving symptoms. Several have been studied, including one that stays mostly in the gut. Methane overgrowth may be treated with a different combination. Your gastroenterologist will choose based on your test results and health history. When slow movement through the gut is part of the problem, MedlinePlus notes that medicines that help the intestines move may be added.

The guideline stresses that antibiotics aren’t harmless, because overuse can lead to resistant bacteria and infections such as C. difficile. That is why the ACG recommends confirming SIBO before treating, rather than treating on a hunch.

Diet

Diet changes for SIBO aim to cut down on fermentable foods. Some people feel better with a low-FODMAP approach, which limits certain sugars and fibers that gut bacteria ferment. The ACG notes that diet evidence for SIBO mostly comes from IBS studies. If you try one of these diets, a dietitian can help you keep it balanced and add foods back over time.

Probiotics

The ACG found no consistent evidence to recommend specific probiotics for SIBO. It also found no basis for using fecal transplant as a treatment for SIBO.

SIBO treatment at home: what helps and what doesn’t

Many people search for ways to treat SIBO at home or naturally. Some home steps are useful alongside medical care, but none of them replaces testing and a plan from your doctor.

Eating in stages. A practical approach is to start with a short period of gentler, lower-fermentation meals while treatment works. Your doctor or a dietitian can suggest simple meals that are lower in the sugars and fibers gut bacteria ferment. As symptoms settle, you add foods back one group at a time, so you learn what truly bothers you. The goal is the widest diet that keeps you comfortable, not strict avoidance for life, and a dietitian can help you get there.

Dairy. MedlinePlus notes that a lactose-free diet can be helpful for some people with SIBO. If milk seems to make your bloating worse, ask your doctor whether to try cutting back.

A symptom log. Writing down a daily bloating score, your bowel pattern and the meals that seemed to help or hurt gives your doctor something concrete to work with. Bring it to your follow-up visit.

Herbal products and supplements. Herbal antimicrobial blends are widely sold for SIBO, but the research behind them is limited and mostly small studies. The FDA does not approve dietary supplements for safety before they are sold, and some herbs interact with prescription medicines. Probiotics have the same problem, as noted above. Talk with your gastroenterologist before you try any of them, especially if you take other medicines.

Can SIBO be cured, or will it go away on its own?

Treatment often relieves symptoms, and for some people SIBO does not come back. Whether it stays away depends mostly on the reason it started. The ACG describes SIBO as something that almost always grows out of another problem, such as slow gut movement or a change from surgery. If that problem is still there, bacteria can build up again even after a good response to antibiotics.

There is little research on SIBO clearing up without treatment. Because the underlying cause usually persists, waiting it out is not a reliable plan, especially if you have weight loss, fatty stools or low vitamin levels. MedlinePlus notes that severe cases can lead to malnutrition and problems caused by low vitamin levels. A visit with a gastroenterologist can sort out whether SIBO is the real cause of your symptoms and what is driving it.

What comes next: why SIBO comes back

SIBO often returns after treatment, and the ACG cites one study that measured how often. In that study, it came back in 12.6% of people at 3 months, 27.5% at 6 months and 43.7% at 9 months after antibiotics. The best protection is treating whatever allowed it to develop in the first place, such as a motility problem or a medicine that slows the gut. The ACG calls this the primary approach to prevention, because it helps avoid repeated rounds of antibiotics. Some people with SIBO that keeps returning still need more than one course, and the AGA advises doctors to weigh the risks of long-term antibiotic use each time.

When to see a gastroenterologist

Get urgent or emergency care for severe or worsening belly pain, a swollen and hard belly, vomiting that won’t stop, black or bloody stools, or signs of dehydration such as dizziness and very little urine.

Make an appointment with a gastroenterologist if you have any of the following:

• Bloating, gas or diarrhea that has lasted more than a few weeks
• Weight loss you can’t explain, or fatty, oily stools
• Low iron or vitamin B12 on blood work
• Digestive symptoms after abdominal surgery, or with diabetes or scleroderma
• SIBO that keeps coming back after treatment

Ongoing bloating and diarrhea are worth a proper workup rather than guesswork, and our gastroenterologists at GI Associates in Wausau, Stevens Point and Wisconsin Rapids look for the cause and perform upper endoscopy or colonoscopy when they are needed. If bloating has been going on for weeks, request an appointment.

This article is for general education and is not a substitute for medical advice. Talk with your doctor before starting, stopping or changing any medication.

Sources

1. Pimentel M, Saad RJ, Long MD, Rao SSC. ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth. American Journal of Gastroenterology. 2020;115(2):165-178. https://doi.org/10.14309/ajg.0000000000000501
2. Quigley EMM, Murray JA, Pimentel M. AGA Clinical Practice Update on Small Intestinal Bacterial Overgrowth: Expert Review. Gastroenterology. 2020;159(4):1526-1532. https://pubmed.ncbi.nlm.nih.gov/32679220/
3. Rezaie A, Buresi M, Lembo A, et al. Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus. American Journal of Gastroenterology. 2017;112(5):775-784. https://doi.org/10.1038/ajg.2017.46
4. MedlinePlus (U.S. National Library of Medicine). Small bowel bacterial overgrowth. https://medlineplus.gov/ency/article/000222.htm
5. U.S. Food and Drug Administration (FDA). Questions and Answers on Dietary Supplements. https://www.fda.gov/food/information-consumers-using-dietary-supplements/questions-and-answers-dietary-supplements