Do sulfur burps mean I have the hydrogen sulfide type?

They are frequently described alongside it, and in one registry only 10% of confirmed cases reported them, which is the opposite of the impression the internet gives. A symptom present in a minority of confirmed cases cannot identify the condition, and the main guideline says no single symptom can be attributed to overgrowth at all.

My test was negative. Have I ruled this out?

Only if the test measured it, and most do not. A two gas test returning negative has said nothing about hydrogen sulfide in either direction. That is a different situation from a negative result, and reports rarely make the difference visible.

Why is there no threshold for it?

No consensus body has set one. The North American Consensus covers hydrogen and methane and contains no hydrogen sulfide criterion, so even a test that measures the gas returns a number with nothing published to compare it against.

The hydrogen sulfide type

By BeatSIBO editorial team · Updated August 8, 2026

This is the type where the gap between what is measured and what is claimed is widest, in both directions.

The asymmetry

The short answer

Hydrogen and methane have published cutoffs and are measured by most tests sold. Hydrogen sulfide has neither. It is measured by very few tests, and no consensus body has published a threshold for what a number would mean. So this type is real, discussed constantly, and the least resolvable of the three on paper.

Rezaie A et al., American Journal of Gastroenterology 2017 Clinical guideline

The consensus sets thresholds for two gases and contains no hydrogen sulfide criterion at all.

A negative is not a finding here

The short answer

Most breath tests measure two gases and physically cannot register the third at any concentration. A negative from one of those is silence about hydrogen sulfide rather than evidence against it. On a report the two look identical, which is the single most expensive misunderstanding in this subject.

Someone buys the cheaper test, gets a negative, and concludes the question is settled. It is not settled. It is unmeasured, and those are different things.

What the symptom figures actually say

Goldenberg J et al., medRxiv 2023 Preprint, not peer reviewedA preprint drawing on a practitioner-sourced convenience sample. Not peer reviewed, and the sample is self-selected by clinicians who were already looking for hydrogen sulfide.

Read the caveat attached to that citation before the numbers. It is a registry of people already confirmed positive, so the percentages describe that group and are not prevalence figures for anybody else.

Bloating
Share of confirmed cases:
77%
Constipation
Share of confirmed cases:
50.8%
Diarrhea
Share of confirmed cases:
42.6%
Sulfur burps
Share of confirmed cases:
10%

Reported symptoms among confirmed hydrogen sulfide cases
Symptom	Share of confirmed cases
Bloating	77%
Constipation	50.8%
Diarrhea	42.6%
Sulfur burps	10%

These describe people already confirmed positive. They cannot tell you how likely you are to be positive, and the symptom most associated with this type online appears in one case in ten.

The sulfur burps figure is the interesting one. It is the symptom most confidently attached to this type in popular writing, and it appeared in one confirmed case in ten. That is not a reason to dismiss it. It is a reason to stop using it as an identifier.

What is not settled here

That registry is a preprint and its figures come from a self-selected confirmed group, so we report them as a description of that group and nothing more. The wider problem is that this type is discussed far more than it is measured, so most of what circulates about it rests on people describing their own experience rather than on anything with a denominator.

Overlap is common

Around a quarter of that registry were positive for hydrogen sulfide and another gas at once. Treating the three types as separate boxes is tidy and not accurate, and a report naming one gas has not excluded the others unless the test looked for them.

Pimentel M et al., American Journal of Gastroenterology 2020 Clinical guideline

Against all of that, the guideline states that no single symptom can be specifically attributed to overgrowth. Which is the honest summary of this page: the type is worth knowing, and it is not knowable from how you feel.

Common questions

Do sulfur burps mean I have the hydrogen sulfide type?: They are frequently described alongside it, and in one registry only 10% of confirmed cases reported them, which is the opposite of the impression the internet gives. A symptom present in a minority of confirmed cases cannot identify the condition, and the main guideline says no single symptom can be attributed to overgrowth at all.
My test was negative. Have I ruled this out?: Only if the test measured it, and most do not. A two gas test returning negative has said nothing about hydrogen sulfide in either direction. That is a different situation from a negative result, and reports rarely make the difference visible.
Why is there no threshold for it?: No consensus body has set one. The North American Consensus covers hydrogen and methane and contains no hydrogen sulfide criterion, so even a test that measures the gas returns a number with nothing published to compare it against.