By Dr. Ian McLogan, ND

In this short post I highlight IBS, what it is, and how I diagnose it and approach treatment options. My approach is based on research and my clinical experience. 

IBS: What it is and what it isn’t

Irritable Bowel Syndrome (IBS) refers to specific symptoms in the gut, including abdominal pain, that occur without visible damage to the colon. The lack of visible injury is what makes IBS a functional disorder, meaning only the function of the gut is impaired, not the integrity of the digestive system itself. This doesn’t minimize the disorder; in the case of IBS, digestion can be very uncomfortable, or frankly painful. 

It’s not all in your head

Because there are no visible hallmarks of disease, IBS was misunderstood for a long time as a psychological disorder. For this reason, still today, SSRI’s and other anti-depressants are still considered viable treatments for IBS by some (including insurance providers). Thankfully that is changing, and there is now a large body of research exploring underlying causes and alternative treatment options. 

So you say you have abdominal pain…

Most people reading this post likely either have IBS, know someone with it, or suspect they may have it. And it’s no wonder; estimates range, but one recent study indicates IBS up to 23% of people worldwide. [1] Knowledgeable physicians can diagnose IBS clinically, with the help of the Rome IV Criteria. To qualify for diagnosis, a person’s symptoms must meet the following criteria and not have any other disease that could cause them: [2]

Recurrent abdominal pain at least 1 day per week in the past 3 months, and also two of the following: 

  • Pain must be related to defecation
  • Pain is associated with change in frequency of stool
  • Pain is associated with change in form (appearance) of stool

Also, bloating and abdominal distension are also now becoming widely recognized as associated symptoms, but do not contribute to a diagnosis. 

But why?!

So what causes IBS? The short answer is…a lot of different factors. There is no scientific consensus on one cause for IBS. It seems to be a multifactorial syndrome. Some of the causes include: [1,3,4]

  • Small Intestinal Bacterial Overgrowth (SIBO), which happens when bacteria grow in the small intestine, where they shouldn’t.
  • Post-infectious immune alterations, such as when a person’s digestion is never the same after traveler’s diarrhea.
  • Motility issues and changes in transit time (how fast or slow food and waste travel through the gut).
  • Food sensitivities and intolerance to fermentable foods that feed bacteria (FODMAPs).
  • Serotonin dysregulation, a neurotransmitter involved in communication between your gut and your brain.

All of the above warrant separate discussions, but they offer a glimpse into why IBS can be so challenging to treat. 

So now what?

How do I typically treat patients with IBS? I look for the cause, after ruling out other diseases. This is not always easy; often patients don’t remember a time when they felt well, and the symptoms can be normalized within families. But my first step is listening to the patient, and taking a detailed history. Learning about the beginning of the symptoms gives me clues about the cause. SIBO, for example, can be triggered by long term use of some drugs for heartburn, or after a round of antibiotics. Sometimes I order lab tests, which could include a breath test for SIBO, or a stool test for pathogenic gut bugs. However, other causes like food sensitivities are not always easy to tease out, and require a different approach. Ultimately, before IBS can be treated, the cause must be identified.

And how do we fix it?


If there is evidence to support a SIBO diagnosis, antimicrobial treatment is often employed, in the form of herbal formulas or pharmaceutical drugs. The same is true for other types of gut infections found on a stool test. Additionally, some bacteria or other organisms can form protective films around themselves, called biofilms. In these cases, I may treat with agents that target them.


I often utilize dietary treatments, since assessing likely triggers in the diet can help tremendously. Options include the Low FODMAP Diet or a tailored elimination-challenge diet. I personally like Monash University’s approach, as they combine both to a certain degree. Additionally, there are other good resources available, including IBS specialist Dr. Allison Siebecker’s website.

Restore movement

Motility, or the pace of movement through the gut, is another area of treatment I often explore. This can be especially helpful with the IBS constipation type, but is also often quite useful for diarrhea-predominant IBS. These treatments can range from very gentle herbal therapies to prescription medications.

To wrap it all up…

Overall, this is just a brief look into IBS, the many contributing factors, and possible treatments for a debilitating syndrome that affects so many people. If any of the symptoms discussed previously sound familiar, or you think you may have IBS, the best course of action is to meet with a qualified doctor. Licensed Naturopathic Doctors are experts in identifying and treating the many causes of IBS, and will take the time to address your particular needs. 


  1. Saha L. (2014). Irritable bowel syndrome: pathogenesis, diagnosis, treatment, and evidence-based medicine. World journal of gastroenterology, 20(22), 6759–6773. doi:10.3748/wjg.v20.i22.6759
  2. Lacy, B. E., & Patel, N. K. (2017). Rome Criteria and a Diagnostic Approach to Irritable Bowel Syndrome. Journal of clinical medicine, 6(11), 99. doi:10.3390/jcm6110099
  3. Lehrer, J. K. (2018, August 09). Irritable Bowel Syndrome. Retrieved from
  4. Irritable Bowel Syndrome. (2019). Retrieved from