Sulfur Burps: Causes (Giardia, SIBO, GLP-1) and What Helps

Sulfur burps are belches that smell like rotten eggs because they carry hydrogen sulfide, a gas bacteria release when they break down sulfur-containing protein^[1]. Most cases follow a large protein-rich meal, swallowed air or reflux. Persistent sulfur burps with diarrhea can point to giardiasis or small intestinal bacterial overgrowth (SIBO), and they are often reported with GLP-1 medicines^[2].

No study has measured hydrogen sulfide in burps directly, so the links below are plausible mechanisms, not proven ones. This guide ranks the causes, explains how to tell them apart, and covers what helps and when a symptom needs a doctor.

Get medical help promptly if sulfur burps come with black or tarlike stools, bloody vomit, frequent vomiting, trouble or pain swallowing, weight loss you did not intend, or severe constant abdominal pain^[3]. These can signal bleeding, an ulcer or another problem that needs a clinician, not home care. See our guide to black stool for how to tell bismuth from bleeding.

Why do burps smell like rotten eggs?

A burp is gas leaving the stomach through the mouth^[4]. Swallowed air is the usual source, and it carries no sulfur smell on its own. The rotten-egg note comes from hydrogen sulfide (H2S), which is among the main malodorous compounds in flatus^[5].

Gut bacteria make H2S from sulfur-containing amino acids, so sulfur-rich foods, especially meat protein, are the main dietary driver studied. In a controlled feeding study of five men, fecal sulfide rose from 0.22 mmol/kg on a meat-free diet to 3.38 mmol/kg on 600 g of meat a day^[1]. Sulfate-reducing bacteria, which live in the colonic lining, produce H2S as a by-product of hydrogen metabolism^[6]. Species such as Desulfovibrio piger and Bilophila wadsworthensis belong to this group.

What causes sulfur burps?

Most sulfur burps have an ordinary cause. The table ranks the common ones by how often a clinician would expect them, with the clue that separates each.

Do sulfur burps mean Giardia?

They can, but burping is a minor feature of giardiasis. The CDC Yellow Book describes Giardia duodenalis infection as causing abdominal pain, bloating, "sulfur" belching and vomiting, and it spreads through contaminated water and sometimes vegetables^[8]. A review of published case series found belching in about 26 to 30 percent of patients, against 53 to 85 percent for abdominal cramps^[9].

The pattern that raises suspicion is diarrhea plus gas, cramps and smelly, greasy stools. Symptoms usually start 1 to 2 weeks after exposure and last 2 to 6 weeks, and they can seem to clear and then return^[10].

The CDC lists tinidazole, nitazoxanide and metronidazole among effective drugs, and advises testing 3 stool samples over several days when infection is in doubt^[11]. Only a clinician can prescribe these. Our Giardia guide covers the long-term effects, including post-infection IBS, and the diarrhea page covers what to do while it lasts.

Can SIBO cause sulfur burps?

It may. Belching is among SIBO's symptoms, but the symptoms are nonspecific and do not predict a positive test, so a smell alone proves nothing^[12]. In the same review, hydrogen and methane breath-test thresholds define a positive result, and rifaximin cleared SIBO in 70.8 percent of patients across 26 studies, with about 44 percent relapsing within 9 months^[12]. The ACG guideline covers who should be tested and how^[13].

The AGA advises SIBO breath testing only for a small subset of at-risk patients with belching or bloating^[14]. For the full picture of symptoms and treatment, see our SIBO page.

What do sulfur burps with diarrhea, vomiting or stomach pain mean?

Sulfur burps with diarrhea usually point to the gut rather than to a single meal. The leading explanations are an infection such as Giardia, SIBO, a GLP-1 medicine, or gastroenteritis, and the extra symptoms help sort them.

Dehydration is the main short-term risk of ongoing diarrhea, and it is especially dangerous for infants and pregnant patients^[11]. Replace fluids and see the diarrhea guide.

Are sulfur burps normal on Ozempic, Wegovy, Zepbound or Mounjaro?

They are commonly reported, but the data are about belching, not smell. Ozempic and Wegovy contain semaglutide; Mounjaro and Zepbound contain tirzepatide. In a pharmacovigilance analysis of tirzepatide reports, eructation (belching) had the highest disproportionality of any stomach or bowel event, and most events began within 3 months, a median of 16 days after the first dose^[2].

The authors link the drug's slower stomach emptying to bloating and nausea^[2]. The reports show how often belching was reported, not how often it smelled of sulfur.

A 2025 meta-analysis of 55 randomized trials (106,395 participants) found GLP-1 drugs raised the risk of GERD (relative risk 2.19) and gallstones (1.46) but not of other stomach or bowel events, including gastroparesis^[16]. Mayo Clinic authors suggest starting with smaller, more frequent meals, adequate hydration, and avoiding high-fat or high-sugar foods^[15]. Do not stop or change a prescribed dose on your own; raise persistent burps, vomiting or pain with your prescriber. Our GLP-1 and probiotics guide covers the microbiome side.

Could H. pylori or reflux be behind it?

Possibly. The ACG and CAG dyspepsia guideline recommends non-invasive H. pylori testing and treatment for people under 60 with dyspepsia, then a trial of a proton pump inhibitor if that does not help^[17]. In a meta-analysis of 29 trials, eradicating H. pylori improved functional dyspepsia modestly, with a number needed to treat of 14^[18]. Read more on H. pylori. Reflux can also bring up gas; see GERD.

How do you get rid of sulfur burps?

Treat the cause first, and use these steps meanwhile.

1. Swallow less air. Avoid gum, hard candy, fizzy drinks and straws, do not talk while eating, and eat slowly while seated^[7].
2. Eat smaller, more frequent meals and trim your own triggers, such as cruciferous vegetables, legumes and sugar-free "-ol" sweeteners^[7].
3. Ease off heavy protein loads. Fecal sulfide tracked meat intake in the feeding study^[1]. That study measured stool, not burps.
4. Consider bismuth subsalicylate (Pepto-Bismol) short term. It binds H2S, and in 10 healthy adults it cut fecal H2S release by more than 95 percent at 524 mg four times a day for 3 to 7 days^[5]. Follow the label, not that research dose. MedlinePlus says to stop and call a doctor if diarrhea lasts over 48 hours, and to check first if you take blood thinners, take aspirin daily, are allergic to salicylates, or have an ulcer or black or bloody stools, and to ask a doctor first if you are pregnant or breastfeeding^[19].
5. Test the fiber angle cautiously. In lab fecal slurries, resistant starch cut H2S production by 89 percent and fructo-oligosaccharides by 82 percent, while cysteine boosted it^[20]. It is a lab result, and more fiber can also cause gas in some people.

We found no trial of antacids, digestive enzymes or probiotics for sulfur burps themselves. Probiotics did improve SIBO decontamination in a meta-analysis^[21], which is why they come up. See probiotics and gas and enzymes versus probiotics.

When to see a doctor

See a clinician if sulfur burps last more than a few weeks, come with diarrhea for more than a week, or follow travel or untreated water. Go right away for chest, jaw, neck or arm pain, trouble or pain swallowing, frequent or bloody vomiting, severe constant belly pain, unintended weight loss, loss of appetite, yellow skin or eyes, or black, tarlike stools^[3]. The ACG and CAG guideline suggests endoscopy for people 60 or older with new dyspepsia^[17], and the AGA reserves upper endoscopy for alarm features or worsening symptoms^[14].

This article is for general educational purposes and is not medical advice. It does not replace testing or an exam, and sulfur burps have many causes. Talk to a qualified healthcare professional before starting bismuth subsalicylate, probiotics or any treatment, particularly if you are pregnant, immunocompromised, taking prescription medication such as a GLP-1 drug, or managing a diagnosed condition.