Sulfur burps with diarrhea usually mean that bacteria (or, less often, a parasite) are fermenting food too quickly, too high up in your gut. The most common causes are simple: a heavy, sulfur-rich meal, food poisoning or a stomach bug, and GLP-1 medications like Ozempic and Mounjaro. These tend to clear up within a few days. When the combination keeps going, the two causes most worth ruling out are giardia, a parasite that classically causes eggy burps with greasy, foul-smelling diarrhea, and SIBO, particularly the hydrogen sulfide type.
Most cases settle within 48–72 hours with fluids, lighter food and, for adults who can take it, Pepto-Bismol. See a doctor if the diarrhea lasts more than a few days, keeps coming back, started after travel, camping, antibiotics or drinking untreated water, or comes with fever, blood, severe pain, weight loss or signs of dehydration.
Key Takeaways
- The rotten-egg smell is hydrogen sulfide, made by gut bacteria breaking down sulfur. Diarrhea alongside it points to fast, heavy fermentation or an infection.
- Short-lived (1–3 days): usually a heavy meal, food poisoning, a stomach bug or a GLP-1 dose increase.
- Lasting or recurring: think giardia, hydrogen sulfide SIBO, lactose intolerance, or a problem after antibiotics.
- Giardia causes diarrhea in over 90% of people with symptoms and often leaves temporary lactose intolerance. It needs a stool test and prescription treatment.
- Higher breath hydrogen sulfide has been linked with sulfide-producing bacteria in the small intestine and looser stools.
- Pepto-Bismol treats diarrhea and binds sulfur gas, but it can mask an infection that needs treatment.
- Worry if you have fever, blood, black stools, severe pain, dehydration, weight loss, or symptoms lasting more than a few days.
Why Sulfur Burps and Diarrhea Happen Together
Your gut bacteria make hydrogen sulfide when they break down sulfur-containing compounds, mostly the amino acids in protein foods, plus the sulfates and sulfites in some foods and drinks. Normally that happens slowly and mostly in the colon, so you barely notice. I cover the full mechanism in my main guide to sulfur burps.
When sulfur burps come with diarrhea, it usually means one of two things:
- Too much fermentation, too high up. Bacteria are working on food in the stomach or small intestine, where they shouldn’t be in large numbers. The gas comes up as burps, and the extra fermentation, plus irritation of the gut lining, pulls water into the bowel and speeds things along.
- Something is damaging the gut lining. An infection or parasite reduces your ability to digest and absorb food, so more undigested food reaches the bacteria. That means more gas, more smell and looser stools.
That’s why this combination points away from “I just ate a lot of eggs” and toward something happening in the gut itself, especially if it lasts.
Common Causes of Sulfur Burps and Diarrhea
1. A heavy, sulfur-rich meal
A big protein-heavy meal with eggs, red meat, crucifers, garlic, onion or beer, especially one that’s also fatty, can cause eggy burps and a loose stool or two the next day. It’s usually a one-off and gone within 24–48 hours. If it happens every time you eat a certain way, that’s a pattern worth noting. Dairy on top can make it worse if you’re even mildly lactose intolerant.
2. Food poisoning or a stomach bug
Bacterial food poisoning and viral gastroenteritis can both cause sulfur burps, diarrhea, cramps and nausea. They usually come on suddenly, often with vomiting, and settle within a few days. The priority is fluids. Afterward, some people notice reflux, bloating or burping hanging around for a while; I cover that in acid reflux after a stomach virus.
3. Giardia
Giardia is the classic cause of sulfur burps with diarrhea. It’s a parasite you pick up from contaminated water or food, often after travel, camping, swimming, drinking from streams or wells, or contact with young children in daycare. Diarrhea affects more than 90% of people with symptoms, and abdominal pain, flatulence and bloating are also very common. In some people the infection becomes chronic, causing malabsorption and weight loss [Stephen et al., StatPearls, National Center for Biotechnology Information, 2025]. Foul, eggy burps are one of its best-known complaints.
Clues that point to giardia:
- Symptoms started one to two weeks after travel, camping or drinking untreated water
- Greasy, pale, floating or very foul-smelling stools
- Bloating, cramping and a lot of gas
- Symptoms that drag on for weeks, or come and go
- Tiredness and weight loss
Giardia is diagnosed with a stool test and treated with prescription antiparasitic medicine. It’s important to get the diagnosis, because over-the-counter remedies can ease symptoms without clearing the parasite. One more detail: giardia damages the lining of the small intestine, and acquired lactose intolerance develops in up to 40% of people, sometimes lasting weeks after the parasite is gone [Stephen et al., StatPearls, National Center for Biotechnology Information, 2025]. If your symptoms come back whenever you have dairy after treatment, that’s probably why.
4. SIBO, especially the hydrogen sulfide type
Small intestinal bacterial overgrowth means too many bacteria are living in the small intestine. Standard breath tests measure hydrogen and methane. Methane-dominant overgrowth tends to cause constipation, while newer tests that also measure hydrogen sulfide have identified a pattern linked with diarrhea. In a 2025 study that sampled fluid directly from the small intestine, higher breath hydrogen sulfide tracked with specific sulfide-producing bacteria in the duodenum, and those bacteria were associated with looser stools [Villanueva-Millan et al., Digestive Diseases and Sciences, 2025].
The typical picture is sulfur burps, bloating soon after meals, and loose or urgent stools that keep coming back. SIBO is diagnosed with a breath test and treated with targeted antibiotics under a doctor’s care [Pimentel et al., The American Journal of Gastroenterology, 2020]. Long-term PPI use moderately raises the risk [Su et al., Journal of Gastroenterology, 2018], which is one of the less obvious links between reflux treatment and this problem.
5. Ozempic, Wegovy, Mounjaro and Zepbound
GLP-1 drugs slow stomach emptying, so food sits longer and ferments, which leads to sulfur burps. Diarrhea is also one of their most common side effects, reported by 30% of people on Wegovy vs 16% on placebo [U.S. Food and Drug Administration, Wegovy Prescribing Information, 2025]. Both tend to peak during dose increases and settle as your body adjusts. I cover this fully in sulfur burps on Ozempic, Mounjaro and Zepbound.
6. Lactose intolerance and other food intolerances
If you can’t fully digest lactose, it passes on to gut bacteria, which ferment it into gas and draw water into the bowel. The result is bloating, gas, burping and diarrhea within a few hours of dairy. It can appear for the first time after a gut infection. Celiac disease, where gluten damages the small intestine, can cause a similar pattern and is worth testing for if symptoms are persistent. See gluten and acid reflux.
7. After antibiotics
Antibiotics disrupt the normal balance of gut bacteria, and diarrhea during or after a course is common. Most of the time it’s mild and settles. But diarrhea that’s frequent, watery, or comes with fever or cramping after antibiotics needs prompt medical attention, because C. difficile infection has to be tested for and treated. See antibiotics and heartburn for the reflux side.
8. IBS and gallbladder removal
Diarrhea-predominant IBS often comes with gas, bloating and burping, and some people’s flares include sulfur burps after trigger meals. See IBS and acid reflux. After gallbladder removal, some people get bile-related diarrhea and trouble with fatty meals. See acid reflux after gallbladder removal.
Sulfur Burps, Diarrhea and Stomach Pain
Mild cramping is common with all of the causes above. Pain is more significant when it’s severe, constant, one-sided, getting worse, or comes with fever. Upper stomach pain with sulfur burps can also point to H. pylori or an ulcer. On a GLP-1 drug, severe pain spreading to your back, or pain under the right ribs, needs urgent assessment because pancreatitis and gallbladder problems are listed warnings for these medications.
Sulfur Burps, Diarrhea and Vomiting
All three together, coming on suddenly, is most often food poisoning or a stomach bug. The main risk is dehydration, so small, frequent sips of fluid, ideally an oral rehydration solution, matter more than anything else. Get help if you can’t keep fluids down for more than a day, or if you’re vomiting food you ate many hours earlier, which suggests your stomach is emptying very slowly.
When to Worry: Red Flags
See a doctor promptly, or get urgent care, if sulfur burps and diarrhea come with any of these:
- Diarrhea lasting more than 3–4 days, or coming back repeatedly
- Fever, especially above 101°F (38.3°C)
- Blood in your stool, or black, tarry stools you can’t explain with Pepto-Bismol or iron
- Severe or worsening abdominal pain
- Signs of dehydration: dizziness, a racing heart, very dark urine or passing very little urine
- Unintentional weight loss
- Symptoms that started after travel, camping, or drinking untreated water (giardia testing)
- Symptoms that started during or after antibiotics (C. difficile testing)
- You’re pregnant, over 65, immunocompromised, or it’s a young child
What to Do in the Meantime
Keep fluids up
This is the priority. Sip water regularly, and use an oral rehydration solution if the diarrhea is frequent. Avoid alcohol, fizzy drinks and a lot of caffeine, which can make both burping and diarrhea worse.
Eat bland, low-sulfur food for a day or two
Plain rice, oats, potatoes, bananas, toast, crackers and clear broth are all gentle. Hold off on eggs, red meat, broccoli and cabbage, garlic, onion, dairy, fatty or fried food, and protein shakes until things settle. Then reintroduce them one at a time.
Consider Pepto-Bismol
For adults who can take it, Pepto-Bismol fits this combination well. It’s licensed for diarrhea, has a mild antimicrobial action, which is part of why it’s used for traveler’s diarrhea [Bierer, Reviews of Infectious Diseases, 1990], and its bismuth binds hydrogen sulfide in the gut, reducing the sulfur smell [Suarez et al., Gastroenterology, 1998]. Keep to the label (no more than 2 days), and skip it if you’re allergic to aspirin, on blood thinners, pregnant, under 12, or have a fever or bloody stools. It turns stool black, which is harmless but can hide bleeding. Full details are in Pepto-Bismol for sulfur burps.
The main caution: if the cause is giardia or SIBO, Pepto may make you feel better without fixing the problem. If symptoms return as soon as you stop, get tested.
What about probiotics?
Saccharomyces boulardii has some evidence as an add-on to giardia treatment and for antibiotic-related diarrhea, but probiotics aren’t a substitute for diagnosis and can make gas worse in some people. I go through the evidence in probiotics for sulfur burps.
What Your Doctor Might Test For
- Stool tests for giardia and other parasites, bacterial infections and C. difficile
- Breath testing for SIBO (hydrogen, methane, and at some centers hydrogen sulfide) or for lactose intolerance
- Blood tests for celiac disease, inflammation, anemia and dehydration
- H. pylori testing if you have upper stomach pain
- A medication review, including GLP-1s, metformin, magnesium supplements and long-term PPIs
Conclusion
Sulfur burps with diarrhea usually mean bacteria are fermenting food too quickly and too high in the gut. If it’s short-lived, it’s most likely a heavy meal, a stomach bug or a GLP-1 dose increase, and fluids, bland food and Pepto-Bismol for a day or two usually see it through. If it lasts, keeps returning or started after travel or antibiotics, the likely causes change: giardia, hydrogen sulfide SIBO, lactose intolerance or C. difficile. Those need testing, not guesswork. Fever, blood, severe pain, dehydration or weight loss mean you should see a doctor straight away.
Once any infection is ruled out or treated, what you eat and how you eat becomes the main lever. Large, fatty, protein-heavy meals give gut bacteria the most to ferment, and the same meals drive reflux, burping and bloating. The Wipeout Diet Plan is built around that: a mechanism-first approach to meal size, timing, fat and protein load, and trigger foods that gives your gut less to deal with at once. It was designed first around LPR and silent reflux, the throat-based form that’s hardest to control, but because it works on the same digestive mechanisms, it helps GERD, heartburn and the gassy, bloated side of digestion just as well.
If you want an easier starting point while your gut settles, the Wipeout Food Reference Guide is the essential companion. It lists foods and drinks that suit acid reflux and LPR, with their pH values, so you can rebuild gentle, well-tolerated meals.
Treat it for a couple of days. If it doesn’t clear up, get tested.
Frequently Asked Questions
What does it mean when you have sulfur burps and diarrhea?
It usually means gut bacteria are fermenting food quickly and higher up than normal, producing hydrogen sulfide gas. Short episodes are usually a heavy meal, food poisoning, a stomach bug or a GLP-1 medication. If it lasts more than a few days, giardia and hydrogen sulfide SIBO are the main causes to rule out.
Are sulfur burps and diarrhea a sign of giardia?
They can be. Giardia classically causes eggy burps with greasy, foul-smelling diarrhea, bloating and cramping, often starting one to two weeks after travel, camping or drinking untreated water. It’s diagnosed with a stool test and needs prescription treatment, so see a doctor if that pattern fits.
How long do sulfur burps and diarrhea last?
From a meal or a stomach bug, usually 1–3 days. On a GLP-1 medication, symptoms often settle within a few weeks of reaching a stable dose. If it lasts more than 3–4 days, or keeps coming back, it’s worth getting checked for an infection or SIBO.
Should I take Pepto-Bismol for sulfur burps and diarrhea?
For adults who can take it, it’s a good short-term option. It treats diarrhea and binds the sulfur gas. Don’t use it for more than two days, and avoid it with aspirin allergy, blood thinners, pregnancy, fever or bloody stools. If symptoms come back when you stop, get tested rather than keep taking it.
Can Ozempic or Mounjaro cause sulfur burps and diarrhea?
Yes. GLP-1 drugs slow stomach emptying, which causes sulfur burps, and diarrhea is one of their most common side effects. Both are most likely during dose increases and usually improve with time. Smaller, lower-fat meals help, and your prescriber can slow your dose increases if needed.
What should I eat with sulfur burps and diarrhea?
Stick to bland, low-sulfur foods for a day or two: rice, oats, potatoes, bananas, toast, crackers and clear broth, with plenty of fluids. Avoid eggs, red meat, cruciferous vegetables, garlic, onion, dairy, fried food, alcohol, fizzy drinks and protein shakes until you’re better.
When should I go to the doctor for sulfur burps and diarrhea?
See a doctor if the diarrhea lasts more than 3–4 days, keeps coming back, or started after travel or antibiotics. Get urgent help for fever, blood or black stools, severe pain, signs of dehydration or weight loss, or if you’re pregnant, older, immunocompromised, or it’s a young child.
Research & References
- Clinical overview of giardiasis, reporting diarrhea in more than 90% of symptomatic patients, flatulence, abdominal pain and bloating as common, chronic malabsorption in some, and acquired lactase deficiency in up to 40% [Stephen et al., StatPearls, National Center for Biotechnology Information, 2025].
- Study linking higher breath hydrogen sulfide to specific sulfide-producing bacteria in small intestinal fluid, with those bacteria associated with looser stools [Villanueva-Millan et al., Digestive Diseases and Sciences, 2025].
- American College of Gastroenterology clinical guideline on diagnosing SIBO with breath testing and treating it [Pimentel et al., The American Journal of Gastroenterology, 2020].
- Meta-analysis finding that proton pump inhibitor use moderately increases the risk of small intestinal bacterial overgrowth [Su et al., Journal of Gastroenterology, 2018].
- Wegovy prescribing information reporting diarrhea in 30% of patients vs 16% on placebo, with GI reactions most frequent during dose escalation [U.S. Food and Drug Administration, Wegovy Prescribing Information, 2025].
- Review of bismuth subsalicylate’s antimicrobial actions and its use in traveler’s diarrhea [Bierer, Reviews of Infectious Diseases, 1990].
- Study showing bismuth subsalicylate markedly reduces hydrogen sulfide release in the human colon by binding sulfide [Suarez et al., Gastroenterology, 1998].
David Gray
12 years living with LPR · Consultant & researcher
I've lived with LPR for twelve years — the misdiagnoses, the PPI courses that did nothing, the slow work of figuring out what actually helps. Wipeout Reflux is where I translate the research into plain terms for people stuck in the same place. Every claim here is sourced to peer-reviewed work, and I consult one-to-one with LPR sufferers.