Is SIBO Causing Your IBS Symptoms?

What the heck is SIBO and why is it ruining my life?!

picture of SIBO in the small intesting

Even the good bacteria in the wrong place can make you very sick. That’s what SIBO is about.
© Can Stock Photo

SIBO stands for small intestinal bacterial overgrowth. The reason why you should care is that bacterial overgrowth symptoms are virtually identical to IBS symptoms.

Some people even list it as a cause of IBS.

What is small intestinal bacterial overgrowth?

Usually the small intestine (also called the small bowel) has a fairly low level of bacteria compared to the large intestine.

The large intestine is a wonderland of bacteria, and that’s what it’s supposed to be. The small intestine should have much less, and the kinds of bacteria are not the same.

The small intestine connects to the large intestine.

If bacteria from the large intestine starts to take over the small intestine, well, there goes the neighborhood!

When the small intestine has too much bacteria, people often develop symptoms that look just like IBS.

What causes small intestinal bacterial overgrowth?

First you need to know how some things work.

There is a wave of squeezing that travels through your bowels. It’s called peristalsis. This wave pushes digesting food, and later, well, poop, through your digestive tract.

Peristalsis has a tendancy to keep the bacteria from the large intestine from “going upstream” to the small intestine.

Anything that slows peristalsis, or causes a backup from your large intestine can lead to SIBO. Here is a short list:

  • Diabetes
  • Nerve damage to the bowel
  • Bowel blockages
  • Bowel scarring from surgery (adhesions)
  • Crohn’s disease
  • Scleroderma
  • Alcohol (even small amounts)
  • Any medication that slows the action of the bowel

A recent study showed that even a moderate amount of alcohol can lead to SIBO. One drink a day for women and two drinks a day for men!

What are the symptoms of small intestinal bacterial overgrowth?

If you have IBS, this list is going to sound awfully familiar:

If you have a long bout of SIBO, it can even interfere with how your body gets nutrients from the food you eat.

This can lead to malnutrition, even if your eating a healthy diet!

It can also lead to weight loss, but that’s not the way to lose weight.

Other SIBO symptoms:

Some people with small intestinal bacterial overgrowth report symptoms like body aches and fatigue.

How can a bacterial overgrowth in the small intestine do all that?

When you eat food, especially carbohydrates (bread, potatoes, sweets, etc), the bacteria in your digestive tract eats some of it. That produces gas.

However if you have massive amounts of bacteria in your small intestines, they can do several things.

First of all they eat a lot of YOUR FOOD. So your body doesn’t get it. They can also make it hard for your small intestine to absorb food.

Second, they produce gas which causes bloating and pain.

Next, because of the irritation and pain, your small intestine may start moving too quickly (leading to diarrhea).

When that happens, some of the food your body hasn’t absorbed travels to the large intestine.

The bacteria there have a huge party at your expense!

How can I tell if I have SIBO? How is SIBO diagnosed?

There are two main ways to get a SIBO diagnosis.

One is the hydrogen breath test. The other is by doing a “culture” (counting) of the bacteria from your small intestine.

The SIBO culture diagnosis:

Picture saying no to SIBO bacteria.

If you have bacteria in your small intestine that doesn’t belong there, that needs to be FIXED!
© Can Stock Photo

The culture method is done by passing a long flexible tube – up your nose, down the back of your throat, through your esophagus, through your stomach, and into your small intestine.

Once this magical mystery tube tour reaches it’s destination, the tube sucks up some liquid from your small intestine.

Then the laboratory counts the bacteria. If the amount is really high for the amount of intestinal fluid, then you will likely get a SIBO diagnosis.

The downside (besides the whole process), is that it only samples small areas of the small bowel.

Also it’s expensive!

The hydrogen breath test:

Here is my page about the hydrogen breath test, but in short, you fast (don’t eat or drink anything but water) for 12 hours.

Next the lab folks give you a really sweet drink.

If you have SIBO (or a few other conditions), then the bacteria will start to digest the sugars, and give off a burst of gasses. These gasses show up in your breath, where they can be measured. If you have one burst of gasses that’s pretty normal (the drink has reached your large intestine). If you have two, then you possibly have SIBO.

The downside: it’s only about 60 percent accurate, meaning you could have SIBO that doesn’t show up on the test.

Also, other conditions can cause a positive hydrogen breath test reading.

What is the treatment for SIBO?

I’ve read that once a person has SIBO, it’s hard to get rid of.

One way is with antibiotics like Rifaximin. The trouble is once the antibiotics are stopped the bacteria often return. This leads to frequent or constant antibiotic treatments.

Another way that SIBO is treated is by adding “probiotics”.

Probiotics are basically harmless or even helpful bacteria. Studies have shown that lactobillus salivaris and/or bifidobacterium infantis can help IBS symptoms.

Good luck!

Find out more about other Causes of IBS.

Find out more about the human digestive system.

If you have any experience with SIBO please let me and others know about it in the comments section!


  1. Reply

    Thanks so much for you website. It has been very very helpful!

  2. Reply

    I was recently diagnosed with SIBO and they believe the cause is from my medical history. I have had 7 abdominal surgeries, endometriosis and internal bleeding all which has caused abdominal adhesions/scarring. With each surgery they remove the adhesions and with each surgery they come back within 6 months symptoms being pain, limited mobility, IBS, constipation, gas, nausea, bloating, and poor digestion and malabsorption (I’ve lost 35 lbs in the last 2 years – I’m 5’7″ and weigh 104 lbs). I have followed the SCD diet and taken herbal supplements with some improvement (no more weight loss, bloating, gas and nausea improved, but not gone). My ND has just prescribed an antibiotic protocol and a modified SCD/fodmap diet. Is there any success with treating SIBO caused by adhesions or is recurrence unavoidable?

    • Reply

      My layman’s opinion is that you are on the right track. I don’t know how adhesions cause SIBO or how that works, but talking to your docs, especially an ND in my opinion, is the best approach. Again, in my opinion.

    • Reply

      Hi Lisa,

      I’m in the same boat.. Only 3 surgeries for endo though. How are you now? I’m on herbals but not cured yet.. My sibo is the worst during my period and my hormones are all over the place.


      • Reply

        Hi Kristen-

        I have noticed that my SIBO symptoms are worst near my cycle. Sometimes it’s days before or a few days after it has started. I’m wondering if there is some type of hormonal treatment that can assist with elevated symptoms during my cycle?

        To all the other commenters, I was diagnosed with SIBO over a year ago. I have tried both Xifaxin and natural antibiotics. My SIBO has returned. The most challenging symptom for me is nausea. I have bloating and constipation. Those symptoms are manageable. Nausea wipes me out and impacts quality of life. I’m not sure about my next steps. I am practically in debt from seeing so many doctors, tests, etc. just trying to stay prayerful.


  3. Reply

    I had the breath test a few months ago and was diagnosed with SIBO. I had a colnonoscopy, every stool test know to man, blood work, etc. I have taken Flagyl, Cipro, and Xafaxan. I felt better for a few weeks and now I feel worse than ever. I get constipated for a few days and when i finally have a b m it is followed by urgent diarrhea for a few days. My DR. doesn’t want to give my anymore antibiotics. I am eating a very strict diet, no dairy, except yogurt, no sugar, very low carb, not much left. i lost 23 pounds but now that has leveled off off. I feel like I have lost my life. Horrified to go out…I don’t know what to do.

    • Reply

      Hi, I just found this site, and I totally understand what you are going through. My 12 year daughter was diagnosed with this and at 14 we are getting some days of relief. We are under a dibosis diet and numerous other methods. We take a natural FDgard for the bloating and gas relief and take amytrypline for the anxiety…then courses of xifaxin or doxycyline. Flagyl does not work for her. We eliminate any starch, sugars, preservatives and any store bought yogurts, breads, etc. I will be than happy to pass on what we discovered if you would like

  4. Reply

    I think I have sibo, just finally did hydrogen breath test yesterday and had blood work done on pancreas and nutrient levels and thyroid. Been losing weight frequently, feels like something is stealing my nutrients,vitamins,and minerals. Also, discomfort in upper right quadrant of my stomach for over a year, had hida scan, colonoscopy, endoscopy with 5 biopsies,all negative,3 ultra sounds,all neg. blood work done numerous times, just elevated triglycerides and glucose and cholesterol. Went to Er and they told me about sibo. I’m hoping that’s my problem, last year I was using a lot of pain meds, I think that may have been the cause.
    .does anyone think I have sibo, I will find out soon. I’m preying its sibo and not my pancreas, my doc said he checked my pancreas in the past and it looked fine in blood work and ultra sounds. Pleas help if any one been down this road. Thank u

    • Reply

      Jason, this sounds like a lot of miserable testing and worrying to go through. Once you start talking about elevated triglycerides, and what not, you’re WAY out of my league though. I’m glad to hear your doctor said your pancreas looked okay. I sincerely hope that it IS SIBO, or some other simple thing. Or at least not a dangerous one. At least it sounds like the doctors you’re working with are hitting it from lots of angles.

      My sincere best wishes to you, that you may find an answer soon. – Shawn

  5. Reply

    Wanted to point out that there is a chemical called somatostatin that is released during flight or fight responses or severe stress. It supresses the release of gastrin, hcl, and VIP. One book said it is an inhibitor of many hormones including sexual hormones, thyroid, and growth hormone. Inhibition of the digestive system is one way you can get SIBO because you don’t have enough acid in the stomach.

    That is why it is important not to try to eat when you are upset or stressed.

    Betaine.hcl with pepsin can help if you take it with your food.

    Be sure and take sublingial b vitamins because they get depleted easily since they are water soluble.

    • Reply

      I admit this is over my head. It sounds like the mechanism that allows stress to cause such havoc to people’s lives. Thanks for the info, Susan!

  6. Reply

    Started with loose BM’s, after eating. Acid indigestion w/ regular use of Nexium and alkaseltzer. Certain foods avoided ., raw onions, seeds , nuts , Ice berg lettuce, high fat foods. Told I have diverticulosis. No pain to speak of with these bouts.

    However, recently have started having severe anxiety. Taking Xanax daily along with a Nexium and baby aspirin. Chest discomfort sent me to emergency room. Complete heart work up proved nothing wrong with my heart, even though the doc wants to schedule me for a heart catherization.

    The GI doc has me scheduled for SIBO test and a colonoscopy. Next test , I hope will be Endoscopy.

    One moe thing, I forgot to mention , I’ve had a queasy stomach all my life. Diagnosed w/ IBS AT 19, now 62.

    Bottom line , I am wondering how many of the posters are having anxiety and how are you dealing with it

    Miserable in Oklahoma

    • Reply

      Hi Deborah, I’ve been told by doctors and fellow sufferers that there is a HUGE connection between the brain and the gut. I personally feel that gut problems can cause anxiety, and even depression, and I think it’s a two way street. Anxiety can set off an IBS for instance. At least that’s what I’ve read. Meditation can help, but that’s a serious daily commitment. Then of course there is the xanax, clonopin, ssri route that some doctors take. The heart catheterization is new news to me. Some people have had some serious stress reduction from yoga (which I need to get back to dammit :), and even acupuncture.

      I hope you can find help soon! Shawn

  7. Reply

    Message for Kat if she sees it – thank you so much for the information you very kindly gave about the Chinese formula. My dog is sick with SIBO – finally got a diagnosis – and a vet has finally prescribed the same formula for her. I have been searching for info that it would really help her. Thank you. You have been a ray of hope in all my despair. xx

  8. Reply

    I have a son 23 lost 43 pounds in 41 days. One morning he passed out after terrible pain in abdomen. He had diahrea for days and occasional constipation. He passed out again from the pain MD said you have giardia w/o a positive giardia test and treated him with a flagly type drug four pills for 24 hours he felt better for three days. Then all hell broke lose nausea , vomitting , diareah etc. He has had all kinds of blood work, parasite ova stool , endo, colon, cat scan ultra sound all negative. Now he is having a small intestine work up tomorrow. Oh yeah told he could have a brain tumor as well (negatvie). It sounds as though he could have SIBO . I hoping the MD can start him on an antibiotice tomorrow!! ANd the Probiotic.

    • Reply

      Donna, I just heard back from you via email. Sorry I took so long to answer. I’m so glad your son is doing better!

  9. Reply

    I was diagnosed almost a year ago with sibo. Rifaximin and neomycin 1x each. Plus vsl#3 daily. Meds work for awhile. If ibcan 100% control my diet with scd diet i can keep at bay. Traveling causes a flare. Ended up this past week in ER for IV. Will be back on meds soon. Question I have is probiotics. Seems to be two schools of thought, Dr. Pimental is a no, many others a yes. SCD diet calls for home made yogurt for that version of probitics. What have you found in your research.

  10. Reply

    Here are the details. I did research on a chinese formula that was proven to be as effective as antibiotics with no side effects.I take 1/2 scoop every two hours- 6 scoops a day. I took the formula with me they did use two herbs on the list and then they custom mixed based on the symptoms, gentics, sensitivity, pulse etc. Huang Lian, (Coptis) is the Chinese antibiotic I’ve cut and paste the Chinese medicine formula I found , I sure hope it helps someone that would make me very happy! I believe that it is effective for both SIBO and H pylori, again without side effects!
    The empirical + also scientifically verified formula that is most commonly employed in the treatment of H. Pylori is called Zuo Jin Wan (Left Gold Pill) 左金丸 and is simply composed of Fr. Evodia (Wu Zhu Yu) and Rz. Copidis (Huang Lian) and was proven as effective as the standard Western medicine pharmaceutical treatment which is to use “H-Pac”, a combination of antibiotics taken in combination concurrently. I have used Zuo Jin Wan clinically, and it is usually a 2-3 week period of treatment that is administered + also the treatment of whatever other prime presenting pattern associated with the patient.

    • Reply

      WOW! Thanks again Kat. This looks like something a person should be seeking help with from a Chinese medicine practitioner. I barely know how to pronounce this stuff. But YES. About 19,000 people stop by the site a month. I bet you are helping SOMEONE get an answer they need.

    • Reply

      Kat, how are you doing? I’m a vegetarian with SIBO and HPylori and trying to be healed but not finding much help. I’m super sensitive to just about everything and also have heavy metal encephalopathy from bismuth…so, I need to be super careful what I use. That said, I haven’t come across any vegetarians who’ve found help for SIBO and HPylori, so I’m hopeful you’ll give an update on how you’re doing and what’s working/not working, etc. Thanks to Shawn for the great site!

  11. Reply

    Finally H Pylori diagnosed with a blood test, the first h pylori test was negative the second one 10 mth later was positve. My other dr did not believe that a blood test is accurate he did a stool test and it was negative. My other dr just treated me with Helidac, I couldn’t even function on it, I felt dizzy and so sick it was so bad by the fourth day I ran to the chinese medicine school/clinic where eight people sat around a table and I told them my story and they came with a plan coolest and most effective treatment plan

    • Reply

      AAAAH! Kat, tell us what happened! You say coolest, EFFECTIVE, plan. I’ve always been interested in Chinese medicine, at least as far as acupuncture goes. It was very effective for me with back problems in the past. Please let us know some details! Thanks! Shawn

  12. Reply

    I had a norovirus/winter vomiting bug type illness back in Feb, originaly symptoms were 36 hours of sickness and diarrhoea including vomiting bile. cleared up pretty quick but since then i have stomach and intestinal pain and disturbance most days, stools are loose but still once daily, could this be SIBO? my symptoms seem to fit. doctor has suggested using probiotic yoghurt for a few weeks with L. Casei, what do you think!?

    • Reply

      Sounds good to me. I always recommend that people take their doctors advice rather than something they read on the web. Meanwhile, there is something that is called post-infectious IBS. I have info here on my site about it. You can use the search if you want to find it quickly. Maybe you could talk to your doctor about that if the probiotics don’t work out. Good luck!

  13. Reply

    I’m now really wondering if something eles can cause SIBO I had fever chills, abdomen pressure on the right quadrant dizziness bloating for 10 months, off and today I feel like something is going in on with my kidneys this seems like it is getting worse. I’ve had every test the dr can think of ..except now I go back to a GI Specialist my dr thinks he can look very closely at my appendix and see if somehow it is infected,
    I was so tired of going to the dr tht I decided to go on a medicinal soup fast and take stuff for parasites and alternated with the naturopathic stuff my ND put me on to drain toxins out of the body, I’m so sick I just cannot believe it.

    • Reply

      That sounds completely HORRIBLE! Please let me and others know what you find out. I hope you find your answers soon! – Shawn

  14. Reply

    Went to ER Twice,had fever chills nausea weight loss headached pressure in my abdomen had CATscan. ultrasound blood work, colonscopy and endoscopy all negative, parasite check all negative, Dr told me it was anxiety, which I dismissed. Went to ND who ordered breath test it was positive and high almost off the charts high! So that meant no sugars, no fibers, no coffee or alcohol, no carbs I’m a vegetarian so no meat white rice is fine, plain yogart No SNACKING ever it creates waves of bacteria in the small intestines. I drink fresh ginger tea and take antibiotics and have felt so much better!

    • Reply

      Thanks so much for the information! I believe it will provide hope for others. Shawn

  15. Reply

    Here’s where the Specific Carbohydrate Diet comes in. It specifically targets SIBO. :) Read on about it! I think you’ll appreciate what you learn!


    Gutsy Girl

  16. Reply

    Hey Shawn
    Great site. I was diagnosed with SIBO about a month ago. I took Rifaximin twice a day for two weeks and I still feel the same(a lot of bloating, stomach pain and change of bowel movement which is loose but still only once a day) I am taking the breath test again on Monday. My story was that i would have on and off battle with some bloating for about the last 3 years (by the way i am 49) my Dr put me on Omeprazole 1 a day every day about 3 years ago even though I didn’t have much heartburn. I have had every test done Upper and lower camera work. CAT scan ultrasound(I have gerd or so they tell me and a hiatal hernia). Anyway when i failed my breath test I thought that I had my answer and maybe I do time will tell. I have done some looking online and found some sites that link long term use of Omeprazole to SBIO do to the the stomach not producing enough acid to digest food properly and to aid in killing bad bacteria. I would be very interested in your thoughts on this and any other ideas on SIBO. Your site is full of great information. Thanks for all the hard work you have done to try and help people.


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