Question 1

How do I know whether I have hydrogen-SIBO or methane IMO?

Accepted Answer

A hydrogen and methane breath test, or a small bowel aspirate, is needed to confirm overgrowth and determine subtype. On breath testing, a hydrogen rise of 20 ppm or more within 90 minutes points to hydrogen-SIBO, while methane at 10 ppm or above at any point indicates intestinal methanogen overgrowth. Meeting both thresholds indicates mixed type. Symptoms alone are not sufficient, because hydrogen-SIBO tends toward diarrhea and urgency while IMO tends toward constipation and distension, and the two overlap considerably.

Question 2

Are herbal antimicrobials really as effective as rifaximin?

Accepted Answer

In the Chedid 2014 trial, a structured herbal antimicrobial protocol was at least as effective as rifaximin for SIBO eradication, with 46% versus 34% achieving a negative breath test (p=0.24, meaning the difference was not statistically significant). Among 14 patients who had already failed rifaximin, 57% achieved eradication with herbal rescue therapy. Herbal protocols run 4 to 6 weeks rather than 14 days.

Question 3

Should I take probiotics while treating SIBO?

Accepted Answer

This depends on timing and strain. In active SIBO, adding more bacteria to an already overgrown small intestine can increase gas, bloating, and discomfort. Saccharomyces boulardii is yeast-based and cannot contribute to bacterial overgrowth, so it can generally be used during and after eradication. Bacterial probiotics such as L. rhamnosus GG are typically reserved until after the eradication phase, started at a low dose. High-dose Lactobacillus in active hydrogen-SIBO carries a risk of D-lactic acidosis. If any probiotic worsens symptoms, stop it.

Question 4

Why is meal spacing so important for SIBO?

Accepted Answer

The migrating motor complex is a cyclical pattern of electrical activity that sweeps through the small intestine roughly every 90 to 120 minutes during fasting, clearing bacteria, debris, and undigested food. It only activates when you are not eating, and even a small snack resets the cycle. Spacing meals 4 to 5 hours apart with no snacking between them, plus an overnight fast of 12 or more hours, gives this housekeeping wave its longest uninterrupted window.

Question 5

Why does SIBO keep coming back after successful treatment?

Accepted Answer

Up to 40 to 50% of patients relapse within 9 months when the underlying motility dysfunction or other root causes are not addressed. This is why the protocol treats prokinetic therapy, meal spacing, and root-cause work as primary rather than optional. Recurrent cases warrant re-evaluating migrating motor complex function, untreated H. pylori, ongoing PPI use, thyroid status, and anti-vinculin and anti-CdtB antibodies.

Question 6

What is an elemental diet and when is it worth considering?

Accepted Answer

An elemental diet provides all nutrition in pre-digested form (amino acids, simple sugars, medium-chain triglycerides, vitamins, and minerals) that is absorbed in the proximal small intestine, effectively starving bacteria further downstream. In a 2025 Cedars-Sinai prospective trial of 30 subjects on two weeks of exclusive oral elemental diet, 73% normalized their breath tests and 83% reported adequate global symptom relief. It may be worth considering if you prefer a non-antibiotic approach, have failed antibiotics, have both SIBO and IMO, or are concerned about antibiotic resistance. Cost, palatability, and consuming nothing but formula for 14 to 21 days are the main barriers.

SIBO and IMO Microbiome Protocol: Eradicate and Prevent