The Beginner’s Guide to SIBO: Antibiotics and Diet Recommendations

Beginner's guide to sibo

[Last updated 23rd March, 2017]

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 which dietary changes are scientifically shown to help.

What is SIBO?

What is SIBO?Small Intestinal Bacterial Overgrowth (SIBO) is a digestive disorder characterized by excessive bacteria in the small intestine (1).

These bacteria then ferment (interact with food particles and nutrients) to cause a wide range of symptoms.

Unlike the large intestine (also known as the gut or colon) which contains most of your gut bacteria, the small intestine should not have a large amount of bacteria.

SIBO is uncommon in young and middle-aged adults, but thought to occur in at least 14% of older patients on average (2).

small intestine and large intestine SIBO

Large intestine (colon) is shown in red. Small intestine is shown in pink. Click to enlarge.

Summary: Excessive bacterial growth in the small intestine is known as SIBO. It becomes much more common as we grow older.

Common Risk Factors for SIBO

Common Risk Factors for SIBOResearchers suspect SIBO is caused by a combination of decreased pancreatic enzymes, bile acids, and gut motility.

Consequently, certain health conditions or lifestyle choices may increase your risk of developing SIBO:

  • Gastrointestinal infections: Such as post-infectious IBS (Irritable Bowel Syndrome)
  • Chronic use of antacids: Long-term antacid use (such as omeprazole) 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: Older people in general 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).

Numerous other conditions are linked with increased SIBO risk, but more research is needed. These include hypothyroidism, Crohn’s disease, ulcerative colitis, fibromyalgia, rheumatoid arthritis, Parkinson’s disease and more.

Summary: Your risk of SIBO is greatly increased by several conditions and factors, most often related to reduced function and efficiency of the intestines.

SIBO Symptoms

SIBO symptomsMany SIBO patients experience different signs and symptoms.

These often overlap with other conditions such as IBS. The most common problems are (1):

  • Fatigue
  • Nausea and vomiting
  • Bloating and diarrhea
  • Poor nutrient absorption leading to deficiencies
  • Malnutrition and weight loss.

The intensity of symptoms can differ too.

While some patients may have diarrhea and milder vitamin deficiencies, others may experience severe nutrient malabsorption and impaired digestion (2).

Nutrient deficiencies

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

Vitamin B12 deficiency is one of the most common, alongside the fat-soluble vitamins such as A, D, E and K (2).

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

Summary: SIBO symptoms range from digestive stress to severe nutrient deficiencies. They are often similar to IBS.

Diagnosing SIBO: Hydrogen Breath Test

Diagnosing SIBO: Hydrogen Breath TestSIBO is a severely under-diagnosed condition (2).

This is because a large portion of our small intestines is impossible to reach without surgery.

Fortunately, some non-invasive tests have been designed; namely the Hydrogen Breath test. This same test can be used to detect common food intolerances, IBS and H. pylori infection.

Breath Test for SIBO

The two types of Hydrogen Breath Test used for SIBO are the Lactulose Breath Test (LBT) and the Glucose Breath test (GBT).

Both tests measures concentrations of hydrogen and methane in the breath.

While neither is perfect, the LBT seems to be preferred.


How a SIBO breath test works. Click to enlarge. Image source:

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 specialised 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.

Summary: The best non-invasive method for diagnosing SIBO is with a Hydrogen Breath Test. It could be worth requesting with your doctor if they have been unable to pinpoint your digestive symptoms.

First Line of Treatment: SIBO and Antibiotics

sibo and antibioticsConventional 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.

SIBO is no exception, and antibiotics are the first line of treatment.

Rifaximin is the most well-studied antibiotic for SIBO, with a success rate of about 50% after 1 week. A combination of rifaximin and other antibiotic, neomycin, has been shown to be around 85% effective after 10 days (14, 15).

Recommended therapy according to information from a SIBO symposium in 2014:

  • Patients with a positive hydrogen breath test: 550 mg rifaximin three times per day for 14 days (not missing any doses).
  • Patients with a positive methane breath test: 550 mg rifaximin three times per day + 500 mg neomycin twice a day for 14 days. Alternatively, 550 mg rifaximin three times per day with 250 mg metronidazole three times per day for 14 days.
  • Antibiotics treatment should be followed by a prokinetic (enhances intestinal tract motility) for 3 months, a repeat breath test and then a low FODMAP diet (more on that below).

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

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

Don’t rely on antibiotics

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).

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

Summary: Antibiotics are useful (and often necessary) in the short-term to treat SIBO. However, patients who solely rely on them are likely to relapse. They also kill both bad and good bacteria, which is very harmful to health long-term.

Low FODMAP Diet and SIBO

Common Risk Factors for SIBOFODMAPs 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.

Unfortunately, there has not been much research in this area and the current evidence is not clear.

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 probiotics – additional bacteria – are beneficial (more on that below).

It seems the low FODMAP diet is incredibly helpful when starting off, but requires a bit more flexibility for SIBO when reintroducing fermentable carbs.

Just make sure not to start a low FODMAP diet until you have finished your course of antibiotics. The ‘bad’ bacteria need to be active for the antibiotics to work.

Summary: A low FODMAP diet may help initially by “starving” the problem bacteria in the small intestine. But studies have not yet confirmed it as a reliable SIBO treatment.

SIBO and Probiotics

Sibo and probioticsProbiotics 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).

However to be fair, some research found no significant benefits. One clinical trial on children treated with omeprazole found probiotics did not help, at least not in preventing SIBO (24, 25).

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

Summary: Early studies have found probiotic supplementation may help with SIBO treatment. Its effectiveness has not been proven in clinical trials though, but it’s a promising area. Consider using them after you have completed antibiotic treatment and a low FODMAP diet.

SCD and GAPS Diet Plan for SIBO

SCD and GAPS Diet Plan for SIBOThere is a lot about gastrointestinal diseases and conditions that science does not yet understand.

SIBO is no exception, which is why the perfect diet plan just doesn’t exist yet. Several potential diets have emerged that are worthy of consideration, but we should be cautious and only trial them under medical supervision.

The following two diets are well-supported by anecdotal evidence (testimonials):


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.

Foods allowed:

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

Foods not allowed:

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

Basically it shares many similarities to the low FODMAP diet, but without the scientific evidence or credibility.


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.

Summary: The SCD and GAPS diet have emerged as potential diets to help treat SIBO, however neither was actually designed for this condition. They may be useful, but are not evidence-based.

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Overall Recommendation for Diet and SIBO

It reportedly takes about 2 to 5 years on average for SIBO to be completely corrected.

For this reason it’s important to explore the different treatment options and find what works for you. Unfortunately, there is no single diet guaranteed to treat SIBO 100% effectively.

From the weight of evidence, 2 weeks of antibiotics is warranted first in order to deal with acute symptoms and bacterial overgrowth. A prokinetic may be required afterwards.

This should be followed by a low FODMAP diet to identify any food intolerance. The SCD diet is also something worth exploring, as is probiotic supplementation after a low FODMAP diet.

This all needs to be done under the supervision of your doctor and dietitian.

Beginner's guide to sibo



  1. Starting in 2001 I began to notice I didn’t feel just right, but it came on so gradually and I couldn’t pinpoint the origin.

    There was some nausea, but it would come and go. At mealtime, I would prepare my plate, but half way through eating it, I would get full.

    This went on for years, but why I didn’t figure it out sooner, I don’t know.

    I then noticed, after my noon meal, that I couldn’t eat again that day, it took about 13 hours to digest a meal. So one meal a day is all I could handle.

    After reading about SLOW DIGESTION causing SIBO, I did a stool test and saw A LOT of Pathogenic Bacteria. Now how was I going to get rid of that?

    I decided to kill it off with Iodine. How else could it be done? I knew of no other way. At the time I belonged to the Iodine Group at Yahoo.

    So I found a LAB that made Lugol’s Solution 5% on the west coast of Canada, went to my local Pharmacy and ordered a bottle. The staff didn’t know what it was, when it arrived and neither did the Pharmacist. They were asking me what I used it for.

    At the time I was reporting to the Yahoo Group, how my treatment was going weekly. So I started on a Friday and took one drop each day. The next Friday I started on 2 drops. By the end of the 3rd week at 3 drops daily all the nausea left me after 8 long years. I was so relieved to have found the answer.

    Adding a Thyroid pill really took care of the slow digestion. I complained often to the Group about the bloating and finally a gal was kind enough to point out that a weak Thyroid, would cause digestion to slow down. I never made that connection.

    Of course I continued increasing the Iodine at the same rate until I reached 16 drops per day (100 mg) in 16 weeks, still reporting to the group each week. At 12 drops my Type 2 Diabetes left, at 16 drops I no longer had bladder infections or sinus infections, shrunk my thick Uterus (the doctor was going to order a Hysterectomy very soon) and Uterine and Breast Fibroids disappeared.

    Finally I lowered the dose to a maintenance level.

    Thank you for allowing me to tell my story.

    • Bonnie I just recently read your article that you wrote about SIBO, I just recently was tested myself but have not gotten the results back yet I have been suffering for the past seven years and I’ve been to five gastroenterologist and just keep saying it’s IBS it’s IBS but I’ve had a lot of pain a lot of bloating a lot of fatigue just not feeling myself and I just have been beside myself trying to find out what this is with no help from anybody else could you tell me what group you belong to on Yahoo and how to get there and possibly elaborate a little bit more on the iodine solution I have a nephew who is a pharmacist here in the United States and I’m sure I could probably get him to help me out with that portion of it but I’d like a little bit more information and I’d love to be able to get into The group so that I can share some ideas or possibly hear her and try some ideas if you could just give me the information how to find the group and get in there I’d be greatly appreciative! My email is, if you’d be willing to leave that information then I’d appreciate it as I’m not sure I can find my way back to this very specific page

    • Hi Bonnie,

      I too suffer from years of SIBO, being in the mountain state does not help at all due to all local and surrounding doctors knowing nothing about the condition, nor have they ever heard of it. I have been doing this on my own for 14 years with diet, antibiotics, herbal treatments etc..etc.. the list goes on but nothing has helped. I am willing to give anything a try but was wondering what Brand of Lugol’s Iodine you purchased? I have noticed a lot of so called Lugol’s Iodine fakes out there and want to make sure i am purchasing the correct one and not wasting my money.



    • What kind of thyroid pill??

      • Bonnie, you mention the Lugol’s Solution 5% and then you go on to say that adding a thyroid pill really took care of slow digestion. What type of thyroid pill?

        • Patricia

          What type of Thyroid pill? I guess there are a few kinds on the market and she did start me on a pill that you buy prepackaged from the Pharmacy called ERFA but I reacted badly to it, too many fillers.

          I ended up with Natural Dessicated Thyroid USP which was compounded for me.


    • what is the normal maintenance dose to keep up forever or how long after reaching the 16 drops. you did not explain that very clearly and that is why I am asking . I am not informed on iodine intake so this is a special iodine ordered so a pharmacy iodine for cuts and bruises would not be suitable.My problem is just SIBO>

      • A pharmacy Iodine for cuts etc is NOT to be taken ORALLY. It is a poison. Just for the SIBO, I took the Iodine at 3 drops daily and within three weeks the SIBO was gone. It may take longer for others. It is Lugol’s 5% iodine which you can buy online at Amazon.

        Also, Google this product to learn more.

        I went to 16 drops for other reasons, I thought I explained that. It was to shrink my breast fibroids, my uterine fibroids, improve Diabetes and THIN OUT my dangerously thick Uterine wall. Thanks

    • senthuran says:

      hi bonnie did you take selenium, citaminc C and other supplement as part of your iodine protocol. if yes, how much ?
      also does iodine is effective for methane sibo

  2. R Williams says:

    I am assuming that this is the same as Small Bowel Overgrowth from which I have suffered for many years. My specialist, a consultant surgeon, advised me against probiotics and to this day I have complied with his advice. Recently I have been keeping a complete record of my daily intake in the hope it will provide a clue as to what encourages the recurring bouts of diarrhoea, hopefully this will help me avoid the problems as a cure is not really forthcoming in the near future.

    • You say a cure is not forthcoming? My Testimonial shows that a cure is HERE right now. And I cured my Bacterial Overgrowth and you can too.

      What information did you need that I didn’t supply in my Testimonial above?

      Is it too hard to understand?

      • Marcia Richardson says:

        I don’t understand how your problem is SIBO. I have had it for 25 years and it causes severe diarrhea and cramping. Mine has gotten worse as I have aged – to the point it was lasting 4-5 hours a day. The only thing that helps me completely is Lotronex, which is incredibly expensive if you are on Medicare. Also another help is following the FODMAP diet.

        I don’t understand why iodine. No doctor has ever recommended that before. I have a normal thyroid.
        m. r.

      • BEVERLEY STRATIS says:

        Hi Bonnie interested to know what maintenance dose of iodine is.Also how do you take it.Is it mixes with water.Will g it on the skin daily not work? Must it run thru the gut?

        • Hi Bev

          A maintenance dose (for life) to support Thyroid health plus for the breasts, ovaries and prostate is 2 drops per day of Lugol’s 5% Solution. However to kill off gut bacteria, you need to go slightly higher for a short time. Taken in water, I don’t notice much of a taste.

          Also why would you think it would help with gut bacteria, if you put it on your skin? That is very funny.

          I find this whole blog here, hilarious. Some people read my whole testimonial AND DON’T GET IT. Their reply is like they didn’t even read it, when I included everything possible to encourage them.

          That’s all I can do.

          • M Szalewski says:

            How about a little kindness? Sometimes when people don’t feel well they have trouble processing information. If you’re feeling better you must have a large reserve of grace and patience to draw from and extend to others who are not yet in your admirably healthy condition.

  3. Doctors don’t know everything. I said I had a stool test, identified the pathogenic bacteria, was sick for 8 years, took 13 hours to digest a meal, had terrible bloating and nausea, was called Gastroparesis and lost 70 lbs?

    I wouldn’t wait 25 years to start looking for help.

    Read my story again SLOWLY and see if it meets the criteria of SIBO. Lugol’s 5% Iodine was discovered in 1818 and was the only remedy doctors had for illness, it cured Syphilus in those days. It was made for internal use and treated a lot of serious health problems. As you MUST KNOW, IODINE KILLS BACTERIA and exactly what do you have in your gut? BACTERIA OF COURSE.

    If I looked I might even be able to find Jacques Lugol’s notes on what this Iodine CURED 100 hundred years ago. You however will not benefit from that information because you can’t seem to understand it. Quit thinking about it and buy some, follow my instructions and be surprised. Or stay sick.

    It’s up to you.

    • Wow why the harsh attitude, relax Bonnie
      This article reads like most articles I’ve read on this subject. Take antibiotics but it probably won’t help. Change your diet but that probably won’t help either. It sure would be nice if there was a one size fits all fix, but that is clearly not the case. I have a 17 year old who was recently diagnosed with sibo. I was impressed that the doctor offered to test her for it. Treatment wise she only offered antibiotics. I personally think antibiotics is only a very short term fix if you don’t know why you have it in the first place. Does anyone know why they developed this problem?

  4. Wow why the harsh attitude, relax Bonnie
    This article reads like most articles I’ve read on this subject. Take antibiotics but it probably won’t help. Change your diet but that probably won’t help either. It sure would be nice if there was a one size fits all fix, but that is clearly not the case. I have a 17 year old who was recently diagnosed with sibo. I was impressed that the doctor offered to test her for it. Treatment wise she only offered antibiotics. I personally think antibiotics is only a very short term fix if you don’t know why you have it in the first place. Does anyone know why they developed this problem?

    • Hello

      You say my article reads like most? Look up further and you will see my original story where I used Iodine to kill off the bacteria and it only took 3 weeks. This SIBO is usually the result of slow digestion.

      • BEVERLEY STRATIS says:

        Hi Bonnie did u change yr diet much when u started the iodine treatment?

        • No Beverly, I didn’t change anything. You need to read my Testimonial and MAKE NOTES on how to do it for yourself and what you need to have on hand.

          The dosage and the type of Iodine.

          good luck,



  5. Catherine says:

    If anyone would like to know more information on getting rid of SIBO and IBS, feel free to e-mail me at:


  6. Interesting. Although I think my SIBO was triggered by taking a new probiotic and digestif at the same time I started taking fosomax,(I’ve stopped all 3 but the damage was done) I first thought I had a parasite. I even had the DNA stool sample screening; no pathogens there; I didn’t think SIBO bacteria visibly appeared anywhere except as a result of the SIBO breath test. My breath test said neg for methane & hydrogen separately, but pos for sibo when scores were added together. At any rate, Moda insurance refuses to validate the use of xifaxan for Sibo; they’ll assist with it benefit-wise only after one has tried numerous other antibiotics for IBS. Xifaxan is supposed to only work in the gut so theoretically, not as many side effects. I’ve given up the battle with Moda & have just started a naturopathic regimen of bitters at each meal & a berberine complex that will be rotated with either Neem or oregano oil capsules. I’ve been on the Fodmap diet for several months; I lost weight that I didn’t need to lose. And I didn’t find much else changed for me. Yet the other diets mentioned are diametrically opposed to some of the allowed foods in the fodmap diet. I remain confused about what else I can do. My bathroom business confines itself to the morning. I still wonder if I could have something else going on besides IBS & sibo. I will ask my naturopath about iodine. What a great discovery Bonnie made that worked for her. I’m open to other ideas……Thanks.

    • M Szalewski says:

      Insurance first balked at paying for my Rifaxamin/xifaxan, but my doctor called my insurance company and advocated for it. I guess that was part of an appeal process. It took about a week but I did get the med.
      It worked only somewhat and i’m now weighing what my next step will be.

      • I did 2 rounds of 10 days each of rifaxim and all I got was a yeast infection on day 10 each time. It did nothing to help my SIBO. I have mostly gas and some bloating. I’m now doing Vivonex elemental diet for 14 days , and hope that will help. I think its okay to mix it with teas to make it more palatable and eat spinach broth or eggs for one meal while taking Vivonex.

        • I must say that some people take only Vivonex and no other food other than water for 14 days to 3 weeks, Very strict. but I just could not survive this as I am already underweight.

  7. Joseph Montesin says:

    At the beginning of the article it said that left unmanaged for several months SIBO usually causes several vitamin and mineral deficiencies.
    I am not sure if I have SIBO but after taking strong antibiotics I have gas and belching. I did not take antibiotics to rid of this and I don’t know exactly how I can manage and overcome it.
    Please can you advice?
    Thank you very much

  8. Maureen K. says:

    I’m another one who hasn’t had any luck with doctors, GI specialists included. They all seem to want to diagnose as IBS and be done with it. Terrible belching, gas, bloating and fatigue. I am over 60 and understand that digestion problems increase with aging but have noticed problems since before age 50. I do agree that some probiotics may contribute to SIBO but possibly the encapsulated ones that go through the small intestine without leaking contents may be the best – Renew Life being one of them. I will be asking for a SIBO test, have had CDSA’s before and in the meantime will try the SIBO diet and oregano oil/cat’s claw/olive leaf/digestive enzymes and Betaine before asking for an antibiotic. Iodine is worth a try. I have Hashimoto’s and am on NDT. What’s wrong with the doctors out there who can’t or won’t help with this?

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