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Most people experience an upset stomach or feels bloated from time to time. But if you suffer from consistent and unpredictable bouts of digestive upset — especially diarrhea, constipation, bloating, reflux or gut abdominal pain — there could be an underlying issue with your digestive system.

What is SIBO

SIBO can be challenging to diagnose. Symptoms may vary and can change from individual to individual, based on the types of bacteria that have infiltrated the small intestine.

It can also be challenging to treat or completely eradicate SIBO. This is because various risk factors may be different for every individual.

In a healthy individual, the small intestine is a relatively sterile area of the body where very few bacteria live. Compare that to the large intestine where bacteria colonize to benefit our health in various ways. We co-evolved with bacteria and other microbes — as such, our health is strongly influenced by them.

We need good gut bacteria to thrive in the large intestine, but it's when they begin creeping upward into the small bowel that problems with SIBO can arise.


SIBO symptoms can include diarrhea, constipation, abdominal pain, gas, bloating, cramping, and in severe cases, fat malabsorption, unintentional weight loss, fatigue, brain fog, and nutritional deficiencies.

In some cases, increased inflammation and damage to the gut lining result from this overgrowth.

This type of damage, although usually reversible, includes increased intestinal permeability or “leaky gut” and brush border dysfunction. This dysfunction may co-exist with, or eventually contribute to, additional health problems, such as inflammatory bowel disease or autoimmune disease.

The symptoms you experience due to SIBO depends entirely on which types of bacteria have overrun the small intestine and how aggressively the problem is treated. (Andrew 2007)


Common causes of SIBO include:

Low stomach acid (hypochlorhydria)

Stomach acid is a key antimicrobial substance that is essential for keeping bacteria levels low in the upper digestive tract. This can occur due to nutrient deficiencies or the use of PPI medication that suppresses acid production.

Impaired motility

The movement of the bolus (partially digested food) from the small to the large intestine through the ileocecal valve can be sluggish for some people and it may sit for too long in the small intestine.

When this happens, parts of the bolus begin to putrefy — bacteria begins to grow in the small intestine when it should have already moved through into the large. Motility supplements are specifically designed to address this issue.

Physical deformity or other physical problems

Individual anatomical features such as diverticulosis and abdominal adhesions or scar tissue can prevent timely digestion of food, promoting a higher likelihood of SIBO developing.

Other risk factors that could make you more susceptible to SIBO include:

  • Diabetes mellitus (type II diabetes) or other metabolic disorders
  • Scleroderma or other connective tissue disorders
  • Autoimmune diseases (like lupus, Crohn's disease, or celiac disease)
  • Conditions that compromise the immune system in general (such as HIV/AIDS)
  • Prolonged use of proton pump inhibitors (antacid medication), anti-spasmodic IBS medications, or antibiotics.


There are several ways doctors can determine whether or not you have SIBO. Unfortunately, there's no fail-proof gold standard test to diagnose the condition. As a result, diagnosis can be a combination of testing and professional medical opinion.

In most cases, a gastroenterologist doctor or naturopathic doctor will observe or take note of your reported symptoms in addition to giving you a glucose or lactulose breath test (we recommend doing both along with a fructose breath test).

With either test, the preparation starts with a specific diet, followed by fasting and then drinking the sugar solution. After that, you provide a series of breath samples into specialized tubes which are then sent to the lab.

Each test sugar is tested separately, with at least one day between each one and with the preparation repeated for each.

The purpose of the breath tests is to determine whether or not the solution you ingest stimulates bacteria in the small intestine. If it does, your breath will contain either excess hydrogen, methane, or both.

The presence of one or both of those elements in your test results can contribute to a SIBO diagnosis. New diagnostic testing to measure a third gas - hydrogen sulfide - is currently being developed.

These tests can generate false positives and false negatives. We recommend working with a professional to help you interpret your results and your symptoms.


While a quick search online will reveal many diets that claim to cure SIBO naturally, the only way to completely eradicate the bacteria, and not just achieve symptom relief, is to take some form of antibiotic or antimicrobial.

Effective treatment options come in both prescription and herbal forms.

The powerful, yet targeted, antibiotic Rifaximin (generic name: xifaxan) has been shown in clinical trials to be extremely effective in treating most occurrences of hydrogen SIBO. (Grace 2013)

This drug isn't without potential side effects, however. Some patients who take xifaxan report hives, diarrhea, and C. difficile infection, which then have to be treated after the initial course of antibiotics.

Neomycin is also given when a high level of methane is recorded, and this is often combined with Rifaxamin. Neomycin is ototoxic, meaning it can damage hearing and cause tinnitus, though this may be temporary.

For a more natural approach, there are herbal antibiotic options, including Dysbiocide and FC Cidal (by Biotics Research) or Candibactin-AR and Candibactin-BR (by Metagenics). Allicin extract is considered an effective intervention for those with methane-dominant SIBO.

Keep in mind: with herbal antibiotics, treatment time tends to take a bit longer.

Even though these herbal treatments don't require a prescription, it's important to use them under the guidance of a trained professional.

Should any problems arise, your trained healthcare professional can help guide you in a different direction.

Dietary Support

Diet can’t cure SIBO on its own. But some diets can help you treat your symptoms.

Bacteria predominantly feed on carbohydrates. Limiting carbohydrates — specifically types referred to as FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) is usually an effective way to experience relief.

A low FODMAP diet restricts some foods that would otherwise be considered a healthy contribution to your diet. Vegetables like garlic, onions, cauliflower, and sweet potatoes are all examples of restricted foods on a low-FODMAP diet.

These foods are considered prebiotic foods — foods that feed the good bacteria in your gut and contribute to healthy gut flora. But it’s possible that your symptoms exist due to these same bacteria living in the wrong place (your small intestines). As a result, you might want to restrict them for a set period of time.

The Low-FODMAP diet is not meant to be a long-term solution. FODMAP foods feed the gut flora in the large intestine that helps us digest complex carbohydrates and other foods necessary for health.

Other diets to consider that some have found more helpful than the low FODMAP diet are the SIBO Specific Diet, developed by expert Dr. Alison Siebecker, and Fast Tract Diet (TM), developed by Norm Robillard, PhD.

Once you've gone through the antibiotic treatment of your choice, begin reintroducing these foods systematically with the help of your medical practitioner.

Read our complete guide to the SIBO diet here.

Lifestyle Changes

Some studies link SIBO and other digestive issues (such as IBS) to physical and emotional stress. Stress reduces gastric acid production. Since low stomach acid is one of the causes of SIBO, it's widely accepted that stress may be a potential contributor to SIBO symptoms.

If you believe you suffer from SIBO, take steps to reduce the stressors in your life:

  • Ask for help vs. taking on undue stresses
  • Say no to non-critical requests
  • Find healthy stress-reduction practices such as moderate exercise, meditation, or calling a friend

Once you've treated SIBO with antibiotics and alleviated symptoms with dietary changes, one of the many ways to prevent recurrence is to find stress reduction and stress management practices that work for you.


SIBO can be difficult to diagnose because it can manifest the symptoms of other digestive disorders. Irritable Bowel Syndrome (IBS), for example, shares some of the same symptoms as SIBO. 

Many doctors only treat IBS symptoms, rather than the root cause, meaning a patient could go a long time treating their symptoms without ever receiving a SIBO diagnosis (or medical advice on how to treat it).

Some researchers question whether or not many IBS patients are actually suffering from SIBO. Previously believed to be the result of psychological factors, gastrointestinal doctors and researchers are now considering more physical root causes of IBS, including SIBO. (Ghosha 2017)

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Research Citations

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