You Treated SIBO… but You’re Still Symptomatic


If you've been told you have SIBO (Small Intestinal Bacterial Overgrowth), you've probably gone through at least one round of antibiotics, antimicrobials, or restrictive diets.


Maybe you felt better for a while… but then the bloating, the backup, the urgency came back.


It's a frustrating experience...and unfortunately a common one.


I'm going to help you understand why SIBO is often over-diagnosed and over-treated...and ultimately what a more effective path forward can look like.


So let's start with the obvious question… does SIBO actually exist?


Yes. SIBO is a real condition.


It occurs when bacteria overgrow in the small intestine, where bacterial counts are normally kept very low.


But it's also one of the most over-diagnosed and misunderstood conditions in gut health right now.


Here's what the research actually tells us:


Symptoms like bloating, gas, diarrhea, and constipation are not unique to SIBO. They overlap heavily with IBS, functional constipation and other common gut conditions.


True SIBO is estimated to affect less than 5% of the general population.

IBS affects closer to 10 to 15%.


Bloating plus irregular bowels does not automatically equal SIBO.

And one of the biggest problems is that breath tests, the main way SIBO is diagnosed, are not fully accurate. False positives are well documented.


Which is why a return of symptoms after treatment doesn't always mean the overgrowth came back. In many cases, the original diagnosis may not have been SIBO at all.


There's also something that doesn't get talked about enough: a SIBO diagnosis can sometimes do more harm than good. For people who are already anxious about their gut or prone to food restriction, the dietary protocols that come with SIBO treatment can deepen food fear and make symptoms worse, not better.


SIBO vs. IBS: why this distinction matters


This is where a lot of people get stuck.

IBS (Irritable Bowel Syndrome) and SIBO share many of the same symptoms. But they are not the same condition, and they don't have the same underlying cause.


IBS is primarily a Disorder of Gut-Brain Interaction. It involves how the gut and brain communicate, how sensitive the gut's nervous system is, and how well the gut regulates its own movement.


SIBO, on the other hand, involves actual bacterial overgrowth in the small intestine, typically caused by a specific structural or motility-related reason.


Just because the symptoms overlap doesn't mean the cause is the same.


IBS is far more common than SIBO. So when someone has bloating, irregular bowels, and discomfort, IBS is statistically a much more likely explanation. Treating it as SIBO without a clear reason for overgrowth often leads people through multiple rounds of antimicrobials without ever addressing what's actually going on.


What about constipation specifically?


The relationship between constipation and SIBO is worth understanding on its own.

When the gut moves slowly, a few things happen:

  • Transit time increases, meaning food and waste sit in the gut longer

  • This shift in gut environment appears to favor certain bacteria, particularly methane-producing ones

  • Methane gas can slow transit even further, creating a cycle that worsens constipation and bloating


So yes, there is a real connection.

But here's the key clinical point: constipation should be ruled out and treated first before pursuing a SIBO diagnosis. In many cases, addressing the constipation changes the picture entirely.


Why breath testing has real limitations


Even when testing is appropriate, the results need to be interpreted carefully.


For people with constipation, breath tests are particularly unreliable:

  • Slow transit means the test solution moves through the gut more slowly than it should, causing colonic gases to appear earlier in the test window. This can look like a positive SIBO result when it may actually just reflect slow transit.

  • Retained stool can trap and release gases in bursts, creating false peaks in the test.


For people with diarrhea or loose stool, testing is generally more reliable. And if you meet the criteria for IBS with diarrhea (IBS-D), current clinical guidelines actually support treating with Rifaximin without requiring a positive breath test first. This is one of the more evidence-backed approaches for IBS-D specifically.

Even so, Rifaximin isn't a permanent fix for most people. Without addressing the underlying gut dysregulation, symptoms tend to return.


When does SIBO testing actually make sense?


Not everyone needs a breath test. Testing makes most sense when there's a clear, identifiable reason that bacterial overgrowth could be happening in the first place.


Conditions that genuinely increase SIBO risk include:

  • Reduced stomach acid: from long-term use of acid-suppressing medications (like PPIs), or conditions like achlorhydria or post-gastrectomy

  • Motility disorders: gastroparesis, intestinal pseudo-obstruction, or conditions like diabetes, scleroderma, hypothyroidism, or long-term opiate use that slow gut movement

  • Structural changes to the gut: strictures, adhesions, blind loops, diverticulosis, or fistulas that alter normal flow through the small intestine

  • Ileocecal valve compromise: from surgery or Crohn's disease, removing the barrier between the small and large intestine

  • Pancreatic insufficiency or malabsorption: reduced digestive enzymes can fuel bacterial growth

  • Immune deficiencies: including inherited immune conditions, AIDS, or severe malnutrition

  • Complex multifactorial conditions: celiac disease, cystic fibrosis, liver disease, end-stage renal disease, or short-bowel syndrome


If none of these apply to you, jumping straight to SIBO testing is usually premature.


The same is true if you meet IBS criteria and haven't yet worked through the evidence-based approaches for managing it.


The bigger picture: it's a system problem


This is the part that most people haven't been told.

Chronic gut symptoms, whether that's constipation, diarrhea, bloating, or all three, are rarely caused by one thing. They're often the result of a gut-brain-microbiota (and sometimes pelvic floor) that isn't operating & communicating effectively.


That system includes:

  • Gut-brain communication: the signals between your gut and nervous system that regulate how and when you move your bowels

  • Gut motility: how efficiently your gut actually moves things through

  • Pelvic floor coordination: especially relevant in constipation, where muscle tension can block stool even when everything else is working

  • Visceral hypersensitivity: when the gut's nervous system becomes overreactive, amplifying sensations like bloating, pain, and urgency

  • Microbiome balance: both constipation and diarrhea alter the gut's bacterial environment in ways that keep the cycle going


When these pieces aren't addressed, even the most targeted SIBO treatment won't hold.


So what actually works?


Getting lasting relief means addressing the system, not just the bacteria.


That looks like:

  • Getting a clear, accurate diagnosis before layering in treatments

  • Understanding your specific symptom pattern and what's driving it

  • Building the daily structure your gut needs to regulate itself over time

  • Addressing gut-brain communication, not just gut contents


This is exactly how bloating, constipation, and gut unpredictability get addressed within the Gut Care Roadmap: not as isolated symptoms to suppress, but as part of a bigger picture we work through together, step by step.


The takeaway


If treating SIBO hasn't given you lasting relief, it's probably time to re-evaluate the plan.

We often have to zoom out and look at the bigger picture. The gut-brain system.


Learn more about the Gut Care Roadmap HERE