Is It IBS or Is It SIBO? How to Tell the Difference
Clinically written and reviewed by Dr. Mitchell Schroeder, ND, a licensed naturopathic doctor registered with the College of Naturopaths of Ontario (Reg. #4320). Last reviewed September 2026.
If you have been dealing with bloating, abdominal discomfort, irregular bowel movements, or a gut that seems to react to everything you eat, you have probably come across two terms:
IBS and SIBO.
And if you have searched online, you may have noticed something confusing:
They can look almost exactly the same.
So… which one is it?
The answer is sometimes more complicated than we would like. (Because, as usual with the gut, the answer is rarely just one thing.)
Let’s break it down.
IBS: A Symptom Picture, Not a Single Disease
Irritable bowel syndrome (IBS) is what we call a functional gastrointestinal disorder.
That means there is a problem with how the gut is functioning, but there may not be obvious structural damage that shows up on standard imaging or routine testing.
IBS is diagnosed based on a collection of symptoms, including things like:
Abdominal pain or discomfort
Bloating
Constipation, diarrhea, or alternating between both
Changes in stool frequency or consistency
Symptoms that often fluctuate over time
One of the challenges with IBS is that it is really an umbrella term.
It describes a pattern of symptoms, but it does not necessarily explain why those symptoms are happening.
And this is where things get interesting.
Because IBS can have many different contributors.
SIBO: A Specific, Testable Diagnosis
Small intestinal bacterial overgrowth (SIBO) is different.
SIBO is a specific condition where there is an abnormal amount or type of bacteria present in the small intestine.
The small intestine is not supposed to contain the same concentration of bacteria as the colon. When bacteria move into the wrong place, or grow in higher numbers than they should, they can interfere with digestion and create symptoms.
SIBO can contribute to:
Bloating (especially after eating)
Gas
Abdominal discomfort
Diarrhea or constipation
Food sensitivities
Changes in nutrient absorption
And here is the important distinction:
SIBO is testable.
While IBS is diagnosed based on a symptom pattern, SIBO can be investigated using breath testing to look for patterns of hydrogen and methane gas production.
This means we can often determine whether SIBO is likely contributing to someone’s symptoms — or whether we should look elsewhere.
Why Do IBS and SIBO Look So Similar?
Because SIBO can actually be one of the causes of IBS-like symptoms.
In fact, SIBO is considered one of the more common underlying contributors in people who meet the criteria for IBS.
This is why it can be so frustrating for people who have been told they have IBS.
They may have been given a label, but not necessarily an explanation.
“IBS” tells us what is happening.
SIBO may help explain why it is happening.
But What If It Isn’t SIBO?
This is where we need to avoid oversimplifying things.
Not every person with IBS has SIBO.
There are many possible contributors to IBS symptoms, including:
Changes in gut motility
Food intolerances
Stress and nervous system regulation
Altered gut bacteria
Inflammation
Increased intestinal permeability (“leaky gut”)
Previous infections
Changes in digestion and immune function
Different people can arrive at the same symptom pattern through different pathways.
Two people can both have bloating and constipation, but the reason behind those symptoms may be completely different.
And that matters, because the best treatment plan depends on understanding the underlying drivers.
The Gut Is Connected: Causes Are Not Always Separate
One of the trickiest parts of gut health is that these conditions are not always mutually exclusive.
For example, increased intestinal permeability (often called “leaky gut”) may contribute to IBS symptoms.
But SIBO can also contribute to increased intestinal permeability.
And a person can have both.
The same is true with many gut issues. One problem can create the conditions for another problem to develop.
For example:
Slow gut movement can increase the risk of SIBO.
SIBO can contribute to inflammation and changes in the gut barrier.
Changes in the gut barrier can influence symptoms and immune responses.
Ongoing stress can affect gut motility and digestion.
The gut is not a collection of isolated systems. It is a network.
So… Is It IBS or SIBO?
The answer may be:
It depends.
IBS is a description of a symptom pattern.
SIBO is one possible explanation behind that pattern.
Some people with IBS may have SIBO as a major contributor. Others may have different underlying drivers. Some may have multiple factors happening at the same time.
The goal is not simply to put a label on symptoms.
The goal is to understand what is driving them.
That is why proper assessment matters. Looking at symptoms, timing, triggers, digestion, bowel patterns, lifestyle factors, and appropriate testing can help create a much clearer picture.
Because when it comes to gut health, the question is not just:
“Do you have IBS?”
The better question is:
“Why are you having IBS symptoms in the first place?”
Ready to make a change?
Book a complimentary 15-minute consultation to learn how naturopathic care can help you better understand your symptoms and explore your next steps.
Be well,
Dr. Mitchell Schroeder, ND
Frequently Asked Questions About IBS and SIBO
What is the difference between IBS and SIBO?
IBS is diagnosed based on a pattern of digestive symptoms, such as abdominal pain, bloating and changes in bowel movements. SIBO is a specific condition involving an abnormal amount or type of bacteria in the small intestine. SIBO may be one contributor to IBS-like symptoms, but not everyone with IBS has SIBO.
Can SIBO cause IBS symptoms?
Yes. SIBO can cause symptoms that overlap significantly with IBS, including bloating, gas, abdominal discomfort, diarrhea and constipation. This overlap is one reason further assessment may be helpful when IBS symptoms are persistent or recurring.
How do you know if you have SIBO?
Symptoms alone cannot confirm SIBO because they can overlap with many other digestive conditions. SIBO is commonly investigated using breath testing that measures gases such as hydrogen and methane after consuming a test solution.
Can you have both IBS and SIBO?
Yes. IBS describes a pattern of symptoms, while SIBO may be one factor contributing to those symptoms. It is possible for someone to meet the criteria for IBS while also having SIBO.
What if my IBS symptoms aren't caused by SIBO?
There are many potential contributors to IBS symptoms, including changes in gut motility, food intolerances, previous infections, stress, hormonal changes and alterations in the gut microbiome. A thorough assessment can help determine which factors may be relevant to your symptoms.
How can naturopathic medicine support IBS or SIBO?
Naturopathic care can include a detailed review of your digestive symptoms, bowel patterns, diet, health history and other potential contributors. When appropriate, your Naturopathic Doctor may also recommend further testing or develop an individualized treatment plan based on your assessment.