A healthy and diverse gut bacteria is important for health.

However, an overgrowth of this bacteria in the small intestine – known as SIBO – can cause serious problems.

This article takes a detailed look at SIBO and what dietary changes, supplements, and treatment options are scientifically shown to help as quickly as possible.

● Gastrointestinal infections: Such as post-infectious IBS (Irritable Bowel Syndrome)

● Chronic use of antacids: Long-term antacid use reduces acid production in the stomach. Consistently low levels of stomach acid can lead to bacterial overgrowth in the stomach and small intestine (3, 4).

● Immunodeficiency Syndrome: Disorders that can suppress our immune system – such as AIDS and IgA antibody deficiency – provide an ideal environment for harmful bacteria to thrive (5).

● Celiac disease: Celiac disease can disturb how food moves through the intestines, particularly if it remains undiagnosed or is poorly managed. This leads to increased bacterial growth in the gut (6, 7).

● Aging: In general, older people are at increased risk for SIBO because our digestive tract gets weaker with age. This is thought to be caused by reduced physical activity, weight gain, ongoing medication use and general weakening of the gastrointestinal tract (8, 9).
● Alcoholism: Chronic alcohol consumption appears to increase risk of SIBO (10).
● Gastroparesis: There is a strong overlap between symptoms, and it seems those with gastroparesis (also known as delayed gastric emptying) are more likely to have SIBO (32).

● Fatigue

● Nausea and vomiting

● Bloating and diarrhea

● Poor nutrient absorption leading to deficiencies
● Malnutrition and weight loss.

Left unmanaged for several months, SIBO can cause several vitamin and mineral deficiencies.

Vitamin B12 deficiency is one of the most common deficiencies, alongside the fat-soluble vitamins such as A, D, E and K.

Mineral deficiencies such as iron, calcium and magnesium are also common in SIBO patients.

These two gases are only produced by bacteria (in the small intestine) and not directly by humans. High levels indicate increased bacterial activity and/or overgrowth.

In order to give an accurate reading, prior to the test patients follow a specialized diet for 1-2 days that does not feed the bacteria. On the day of the test, a formulated sugar drink is given in order to get a clear reading of the patient’s reaction to carbohydrates.

The test can be done with take-home kits or with your doctor in the clinic. But interpretation of results should always be with a health care professional.

Diet alone will not rid of SIBO, so you’ll need antibiotics or herbs (or both) as your first line of treatment.

Conventional treatment for unwanted bacterial growth is antibiotics (2).

Antibiotics are designed to kill bacteria, which is why they are prescribed when you have an infection.

RN (I cannot put the full name of the antibiotics here as the search engines may penalize us for mentioning medication) is the most well-studied antibiotic for SIBO, with a success rate of about 50% after 1 week (14, 15).

Here is the recommended therapy, according to information from a SIBO symposium in 2014:

Herbal antibiotics are also an option, with over 50% of patients who fail on RN reporting success with herbal treatment. In this particular study it was Dysbiocide and FC Cidal or Candibactin-AR and Candibactin-BR (16).

Some people may need to do multiple rounds of either herbal or pharmaceutical antibiotics to completely stop bacterial growth.

Just remember that herbal antibiotics must still be taken under the supervision of your doctor. They can interact with other drugs.

The problem with antibiotics, pharmaceutical or herbal, is they do not differentiate between good and bad bacteria — they destroy all bacteria.

Long-term use leads to serious imbalances in your gut bacteria, linked to numerous other health conditions such as insulin resistance and obesity (17, 18).

SIBO antibiotics are also only a temporary “band-aid” treatment, and do not address the root cause of the problem. This is why those only treated with antibiotics are likely to relapse and experience SIBO again (19).

In fact, a study on antibiotic therapy alone versus antibiotics plus guar gum supplementation (a fermentable carb) found that success rates were improved from 62% to 87% with the guar gum added (31).

This seems counter-intuitive because it showed the addition of guar gum (which feeds gut bacteria) was more beneficial than harmful. It’s also in line with studies showing that prebiotics and probiotics – additional bacteria – are beneficial (more on that below).

So, antibiotics are especially useful in the short-term (and often necessary), but are not a permanent solution, and certainly not a solution themselves.

FODMAPs are a type of fermentable carb common in the foods we eat.

They act as necessary “food” for our gut bacteria, but can cause severe digestive problems in sensitive people.

The process of identifying and removing problem FODMAPs from the diet is known as a low FODMAP diet, and is clinically proven to treat IBS (26).

SIBO shares almost all the same symptoms as IBS. In fact, studies show that between 30-85% of patients with IBS also have SIBO (27, 28, 29, 30).

Due to this strong overlap, researchers suspect a low FODMAP diet may be beneficial for SIBO patients too, as it would “starve” the problem bacteria in the small intestine.

Here's the challenge most people face: even though the low FODMAP diet shows promise for SIBO, figuring out which specific foods are safe versus problematic becomes a nightmare.

Most patients tell me they spend hours researching online, only to find conflicting information. One site says garlic is forbidden, another says garlic-infused oil is fine. One list includes carrots, another doesn't. The confusion is overwhelming.

After working with 15,000+ clients with SIBO and microscopic colitis, we've seen this confusion lead to two dangerous outcomes:

1. Over-restriction: People avoid foods they could safely eat, missing out on gut-healing nutrients

2. Accidental sabotage: They unknowingly choose foods that feed their bacterial overgrowth

This is exactly why we created our evidence-based 'Eat This, Not That' FODMAP guide specifically for SIBO and IBS.

Probiotics is the name given to bacteria we intentionally eat for health benefits.

They are essentially the opposite of antibiotics (20).

It seems counterintuitive to treat SIBO – bacterial overgrowth – with additional bacteria, but recent research has seen success using probiotics instead of antibiotics.

One small study of 14 IBS patients with SIBO found that a daily probiotic drink altered fermentation patterns in the intestine, consistent with reducing SIBO (21).

Another early study found that 82% of patients receiving probiotics for 5 days reported improvements compared to only a 52% improvement in those receiving the antibiotic metronidazol. These findings are in line with previous animal studies that observed similar benefits of probiotics (22, 23).

To be fair, though, some research found no significant benefits. One clinical trial on children treated with omeprazole found that probiotics didn’t help, at least not in preventing SIBO (24, 25).

Until we know more, probiotics are not recommended until after completing the antibiotic protocol and a low FODMAP diet.

You also want to be careful of the type of probiotics you are using. Avoid any product with added ingredients like maltodextrin, which can end up feeding the bad bacteria.

The Specific Carbohydrate Diet (SCD) claims to help treat several forms of bowel disease.

This includes ulcerative colitis, Crohn’s disease, diverticulitis and celiac disease.

● Meat, chicken, fish, eggs, some legumes, lactose-free dairy, ripe fruit, non-starchy vegetables, nuts and seeds, and honey.

● All grains, starchy vegetables (such as potato, corn), regular dairy, some legumes, sugar.

Basically it shares many similarities to the low FODMAP diet, but not as much scientific backing at this stage. More studies are underway and I’m looking forward to the results.

The Gut and Psychology Syndrome diet (GAPS diet) is similar to SCD but with a few modifications.

It contains a different introductory phase, fewer legumes, and dairy protein is reintroduced more slowly.

There is some anecdotal evidence to support it, but these are for autism and other conditions related to brain function (hence the name) rather than digestive issues.

There are no studies of the GAPS diet in the medical literature, and the creator makes a lot of extraordinary claims, which is often a red flag.

Enteric-coated peppermint oil has proven to be effective in reducing symptoms like bloating in patients with IBS.

In this study, the researchers found that peppermint oil decreases the production of hydrogen, a bacterial byproduct in patients with SIBO.

Other essential oils — including oregano, tarragon, frankincense, wormwood, and clove oil — may also lend some relief.

Do know that these oils can be potent. Before starting any essential oil regimen, check with a skilled practitioner to help you determine exact dosing.

I get it. SIBO is complex, and the treatment landscape feels overwhelming. 

But here's what I've learned after 6+ years and 15,000+ clients: the people who succeed aren't necessarily the ones who try the fanciest treatments.

They're the ones who avoid the critical mistakes from the start.

And the biggest mistake? Trying to navigate FODMAP implementation without a clear, evidence-based roadmap.

That's exactly why we created our comprehensive 'Eat This, Not That' FODMAP guide. It's specifically designed for people dealing with SIBO and IBS, based on real client results and current research.

This guide eliminates the guesswork, prevents over-restriction, and gives you the confidence to implement FODMAP principles properly from day one.

Remember: SIBO treatment is a marathon, not a sprint. Having the right foundation makes all the difference.