What’s the difference between IBS, IBD, and SIBO? with Dr. Gary Weiner ND, LAc

What’s The Difference Between IBS, IBD, and SIBO

Shivan Sarna interviews guest expert, Dr. Gary Weiner on the topic of IBS, IBD, and SIBO

If you’re having digestive problems, you have enough to deal with without having to keep a bunch of acronyms straight.

But if you go visit your doctor – or do some research on your own – you’ll find a LOT of acronyms – and three of them more than any others: IBS, IBD, and SIBO.

IBS stands for Irritable Bowel Syndrome, IBD for Inflammatory Bowel Disease, and SIBO for Small Intestine Bacterial Overgrowth.

Today, I want to teach you not just what each of these important acronyms means, but what the difference between each is – and, most importantly, how they are all related.

Understanding the link between Irritable Bowel Syndrome, Inflammatory Bowel Disease, and Small Intestine Bacterial Overgrowth can help you get the right treatment the first time.


If your doctor has told you or someone you love that you have any of these conditions (or even if you just suspect it), keep reading. 

What Is IBS?

IBS stands for Irritable Bowel Syndrome.

In Western medicine, “syndrome” is a way of classifying a group of symptoms. Think Chronic Fatigue Syndrome or Restless Leg Syndrome.

In almost any syndrome, doctors use what is called a diagnosis of exclusion. A diagnosis of exclusion just means that there is no other physical explanation for a person’s symptoms.

Imagine you go visit your doctor with stomach pain and diarrhea. They might refer you to a gastroenterologist who performs tests to check for pathological issues, something like Celiac Disease or an ulcer. But if all those tests come back negative  – yet you still have symptoms – you might be told you IBS.

The most common symptom patterns in IBS are abdominal pain, bowel motility disruption like spasms or gastroparesis, diarrhea, constipation (or alternating between both) and pain, bloating and discomfort.

Doctors use something called the Rome Criteria to define what type of IBS a person has:

  • Predominantly diarrhea
  • Predominantly constipation
  • Mixed constipation and diarrhea
  • Post-infectious

(Just FYI – there is some controversy about the Rome Criteria. Not all doctors think it is useful.)

Depending on what type of IBS you have, your doctor might suggest medications or other treatments that can make the symptoms go away or be less severe.

What Is IBD?

Unlike IBS,  IBD (Inflammatory Bowel Disease) is a pathological disease.

That means that there is a pathology  – AKA a cause – for the symptoms that doctors can find.

It gets confusing because IBS and IBD can cause the same symptoms: abdominal pain, constipation and diarrhea, and bloating (to name a few!). But IBS and IBD are different.

Imagine you’re back at your doctor with symptoms. They refer you to a gastroenterologist who performs more tests. But this time, not all the tests come back negative: instead, tests show you have an Inflammatory Bowel Disease.

There are two inflammatory bowel diseases: ulcerative colitis and Crohn’s Disease.

Ulcerative colitis (UC) causes inflammation on the mucosa of the colon. This can cause severe diarrhea, blood in the stool, and lots of pain.

Crohn’s Disease causes inflammation throughout the entire digestive system – anywhere from your mouth to your anus – but the inflammation goes deeper than it does in ulcerative colitis. This is called intramural inflammation.

Treatments for IBD include both medications to manage symptoms (sometimes the same ones used for IBS) and to treat the inflammation in the digestive system.

Why IBS & IBD Aren’t Totally Same OR Different

You might be thinking that it sounds like IBS and IBD are totally different. You either have IBS or you have IBD.

But that actually isn’t all true.

In fact, according to naturopathic physician Dr. Gary Weiner, IBS and IBD are more likely two different ends of the same continuum.

Both IBS and IBD have overlapping features. And even more importantly: the same person can have both IBS and IBD.

This can be confusing for both people with IBS and IBD and for their doctors. They might wonder why treatments don’t seem to be working or why some symptoms went away and others didn’t.

While IBS and IBD can cause similar symptoms, the treatment needed for each can be totally different in some cases  – that’s why figuring out which symptoms are part of IBD and which are caused by IBS is a crucial step in the healing process.

Does That Mean IBS Causes IBD?

Right now, doctors can’t say for certain that IBS and IBD exist on a continuum or that one could cause the other.

But there is evidence to support the idea.

IBS and IBD can have overlapping features like causing:

  • Production of inflammatory cytokines
  • Alterations in the microbiome
  • Inflammation at levels not detectable by colonoscopies or or other standard tests

This evidence has led some experts – like Dr. Weiner – to question if IBS is a precursor to IBD.

After all, many people who are diagnosed with IBD have struggled for years with IBS symptoms – or even have a formal IBS diagnosis. Their tummy troubles seem to have “escalated” into either UC or Crohn’s.

And, just because someone has IBD doesn’t mean they can’t also have IBS. Sometimes people with IBD have an increase of symptoms like diarrhea, pain, gas and bloating. But when they are tested for elevated levels of fecal calprotectin or fecal lactoferrin (two signs of inflammation), results come back normal. This means their IBD isn’t active or “flaring” – they are just having IBS symptoms.

Of course, not everyone who has IBS develops IBD – and not everyone with IBD had IBS symptoms first. But there’s another thing IBS and IBD have in common, too.

What Does SIBO Have To Do With IBS and IBD?

You just learned that IBS and IBD can overlap. Now, imagine 2 circles drawn so they overlap – a Venn diagram. One is labeled IBS, and the other is labeled IBD. Right in the middle where the overlap occurs, that’s SIBO.

SIBO stands for Small Intestine Bacterial Overgrowth, and it can be both a cause and an outcome of IBS and IBD.

SIBO researcher Dr. Mark Pimentel has demonstrated that SIBO is often a root cause of IBS.

And SIBO is also often present in people who have an IBD.

So what’s the difference?

While SIBO is a known cause of Irritable Bowel Syndrome, with Inflammatory Bowel Disease, it’s the other way around: Inflammatory Bowel Disease can cause SIBO.

Let me repeat that because it can be confusing:

SIBO can cause Irritable Bowel Syndrome.

Inflammatory Bowel Disease can cause SIBO.

Is SIBO the Chicken Or the Egg?

Just like the question of the chicken and the egg can be very confusing if you think about it too much, so can the relationship between IBS, IBD, and SIBO.

SIBO is often the cause of Irritable Bowel Syndrome. While there are many other potential causes for IBS, and not everyone with IBS has SIBO, it is estimated that as much as 84% of people who have IBS have SIBO, too.

But there actually isn’t any evidence that SIBO causes Inflammatory Bowel Disease. In fact, it seems to be the other way around: having an IBD can cause SIBO to develop.

The inflammation caused by IBD can create an opportunity for SIBO to develop when normal motility is disrupted.

In basic terms, this just means that when inflammation brought on by UC or Crohn’s causes the digestive system to either slow down (constipation) or speed up (diarrhea), bacteria has a chance to overgrow in the small intestine.

IBD can also interfere with the function of the migrating motor complex (MMC). The MMC is responsible for moving food through the digestive system – some people think of it like a broom sweeping food down the digestive system. When the MMC is interrupted, SIBO can occur.

Why The IBS-IBD-SIBO Link Is So Important

I know that everything we’ve covered so far has been complex and sometimes confusing – but it is really important to understand how Irritable Bowel Syndrome, Inflammatory Bowel Disease, and Small Intestine Bacterial Overgrowth are all related if you want to get healthy again.

If you have SIBO, you (or your doctor) might be confusing it with Inflammatory Bowel Disease. If you IBS, your doctor may not realize it is being caused by SIBO. And if you have Inflammatory Bowel Disease, you might also develop SIBO.

Knowing this is so important for getting effective treatment.

Treating the SIBO within Inflammatory Bowel Disease can help you get better faster and go into remission from IBD. For some people, treating SIBO can cause all IBS symptoms to disappear. And if IBS does often to lead to BID later on, getting IBS under control is even more important.

If you have symptoms of IBS, IBD, or SIBO it’s very important to find out which condition is causing what symptoms. If you treat the SIBO as IBS or the IBD as IBS, you wind up very frustrated and not healing.

Take Ownership & Find The Right Treatment For You

Whether you have Irritable Bowel Syndrome, Inflammatory Bowel Disease, SIBO, or a combination of all three, there is hope for healing and remission.

But, healing starts with become educated and empowered about what is happening to your body! Just like I did, you need to take ownership of your health. That means asking questions, researching, and staying informed.

After all, if you won’t advocate for yourself, who will?

That doesn’t mean you have to become the expert on SIBO, IBS, or IBD. Fortunately, there are many other people who already ARE experts on these complex topics – and they’re willing to share their knowledge with us so we can finally get better.

Check out our courses on gut health here with countless gut health researchers and practitioners. 

Who is your favorite SIBO expert?

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28 thoughts on “What’s the difference between IBS, IBD, and SIBO? with Dr. Gary Weiner ND, LAc”

  1. Hi there I found your site and feed and I am excited. I had my colon resection 9 weeks ago 3/4 is now gone. I had H Pylori before surgery, Thrush during and now SIBO. I also tested positive for Gastroprasis last week. Are all these kinda related or is there more on your site somewhere to look for guidance on diet that helps with all of it together? Also because I am diabetic.


    1. SIBO SOS® Support

      Hi Bobbie,
      I’m so glad you found our work!
      Bowel resection and gastroparesis individually could predispose you to SIBO… and you have both! SIBO management should definitely be part of your long-term toolkit!
      I’d suggest the SIBO Recovery Roadmap Course… under the express supervision of a SIBO specialist especially since you are diabetic. But just to get you started… you can download a copy of Dr. Siebecker’s SIBO treatment protocol. And I also recommend you check out one of her webinars: 9 Steps to Healing SIBO… from Start to Finish
      We are legally prohibited from making any direct referrals. But what I can tell you is that Dr. Mona Morstein is both a SIBO specialist, and it just so happens that she’s dealt extensively with patients struggling with diabetes too. You can find out more about her work at drmorstein.com.
      Good luck! We are rooting for you! Join us in the Facebook group please… we’d love to have you join us on there too!
      SIBO SOS® Support

  2. Hi – I was tested for parasites and Sibo – I have “a few” blastocystis and “many” dientamoeba fragilis. My functional doctor wants to treat the parasites with flagyl for 2 weeks, some herbal therapies, including probiotics – he says treat the parasites first. I’m resistant to the flagyl route. What would you suggest??

    1. SIBO SOS® Support

      Hi Marcia, wonderful to hear from you! We do know Dr. Ilana Gurevich do tend to do the same – parasites first. But of course, it’s a case by case basis.

      There is some side effects to Flagyl, I don’t think we can deny that. However, Dr. Pimentel says that “the metronidazole toxicity, the nervous system toxicity, occurs if you’re taking it again for months and months and months. It doesn’t happen in 14 days. So it’s accumulative dosing.”

      Dr. Morstein also says that it can affect the colon… so that’s another downside. So she tends to give it along with probiotics to kind of mitigate that collateral damage.

      A lot of our experts do tend to use it. And you should absolutely discuss with your practitioner if those side effects outweight the benefits of course.

      Good luck!

  3. Pingback: Low Stomach Acid And Sibos Interview – Reflux that stomach acid

  4. I have been so busy this is the first time I took time to read about SIBO. I have had IBS for 35 years but never knew SIBOwasrealted to it. I would like to learn more about SIBO. Where is the best placebo check. thank you. M Hegner

    1. Maryleigh,
      Check out website at sibosos.com for more information especially click the tab “Stuff We Love” scroll to the bottom and learn about the breath test for SIBO.

      SIBO SOS Team

  5. Thank you for the great article. I really wish i never had to eat again! I was just treated for SIBO. I have n had IBS for years. How do I know if the treatment worked? I had issues with carbs which made me think I had SIBO but I think that is still causing issues n my bowel cycle is out of whack! Any suggestions? Thank u so much 😊

    1. Thank you Lisa for your comments. Dr. Siebecker suggests in the SIBO Recovery Roadmap course, patients know if the treatment worked, by how they feel? She highly recommends retesting after treatment to determine the next steps in protocol. Sounds like you may want to stay on the low Fodmap diet or something similar to avoid trigger foods and slowly integrate different foods into your system in smaller amounts until you can figure out what foods are trigger points. Food diary helps. Obviously, the carbs that are causing your discomfort you will want to avoid. Diet is very much a part of managing symptoms to give your system time to heal. You can visit our website at sibosos.com for our relief guide.

      SIBO SOS Team

  6. Thank you for this wonderfully educational video and the remarks that followed it. I have had symptoms since birth. They’ve waxed and waned over the years but recent surgeries have brought an enormous amount of stress into my life and aggravated my symptoms.
    I live in Alberta, Canada and am struggling with this. My family physician ordered some upper GI tests -barium swallow- and I need to see what the results are. He tells me that a gastroenterologist won’t even look at me until my family doctor has something to give him to warrant a visit. Huh…?? How about all my suffering and the number of things I’ve already tried. It’s tough up here.
    I’m seeing a naturopathic doctor and we’ve discovered that I have very low stomach acid so we’re trying to see if the addition of HCL and Gentiana will, at least, get my stomach back on track.
    I don’t know how to find a physician up here who will help me. Anybody ou know up here? I’ll travel if I have to.

    1. Hi Diane,
      That’s tough! So sorry. We don’t give medical advice, but from my own experience, I highly suggest you discuss with your practitioner adhesion therapy. If you’re not familiar with the term, check out the short video with Dr. Wurn, on our website at sibosos.com Thankfully, your addressing the low stomach acid. Look on our website for our vetted practitioner’s list. If it’s not up yet, email me at in**@si*****.com. Good luck.

      SIBO SOS Team

  7. Where does lymphocytic colitis fit in all this? There doesn’t seem to be very much information around about this once diagnosed apart from recommending steroids which I can’t use.

  8. Mary (Lynn) Mantz-Powers

    I have been dealing with one of these diseases for over 25 years. I have found many foods, drinks and emotions that aggravate my bowels. I’ve been treated with an oral cortisone which caused skin problems and did not relieve symptoms. I now wear a sanitary pad 24/7 which catches “accidents”. We’ve eliminated sex because my husband, a type 2 diabetic, nearly died of a urinary tract infection. This article was interesting and somewhat helpful.

    1. So sorry, Mary. That’s a hard way to live life. Glad you found the blog interesting. Maybe there’s a nugget in there that will keep you keeping on.

      SIBO SOS Team

  9. You say ulcerative colitis is an IBD. What about collagenous colitis? I have that and SIBO, both definitive diagnoses. The first I manage with diet; the second seems to resist all forms of treatment.

    1. Hi Carolyn,
      Great question to ask your doctor. It’s possible your doctor hasn’t found the underlying cause of your SIBO. Keep discussing and letting your doctor know what’s working and what’s not. It’s not unusual to have more than one issue going on at the same time. In fact, is more common.

      SIBO SOS Team

  10. This is interesting…I have struggled with SIBO for years, my mother has struggled with IBS for 30 years and my sister has Crohn’s. There was a time when my sister thought she was having a flare and the doc told her her labs were “fine” but she was very obviously not fine. This article makes that make sense now…her IBD May have not been flaring but perhaps she should also be addressing the possibility of SIBO.

    1. Sounds like it runs in the family genetics. Glad this blog was helpful. Please feel free to share it with your family.

      SIBO SOS Team

  11. Theresa Berthelsdorf

    I have Crohn’s disease and will be getting my terminal ileum, appendix and ileocecal valve removed next week in Portland, OR. Needless to say, I am worried that without the valve, I will develop SIBO. How common is it for Crohn’s patients to develop SIBO post surgery and what can I do now and after surgery to keep that from happening?

    1. Great questions, Theresa. You will want to discuss adhesion therapy with your doctor as well as any preventive measure you can take pre and post-op. Diet is going to be key. Staying close Low FODMap or similar plans. Check out Dr. Siebecker’s website for diet choices at siboinfo.com. Good luck with your surgery. So sorry you’re having to go that route.

      SIBO SOS Team

  12. Unsure of my condition or what to call it. My GI doctor doesn’t seem to be concerned because there is no bleeding. I am miserable every morning with 4-6 soft bowel movements, severe cramping. I have a spastic colan and diverticulosis. I need advise, this is so debilitating.

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