Flatulence (farts) smelling like rotten eggs may be bothersome, but there's likely a straightforward explanation.
A rotten egg smell often comes from bacteria in the large intestine that produce sulfur, a common chemical element. Knowing the cause of the irksome smell can help you find quick relief.
1. Sulfur
The primary cause of flatulence that has a distinctive rotten-egg smell is bacteria in the large intestine releasing gases that contain sulfur.
Some foods that may cause bad gas include:
- Asparagus
- Beans
- Broccoli
- Brussels sprouts
- Cauliflower
- Garlic
- Eggs
- Meat, such as beef, chicken, and turkey
- Nuts, especially Brazil nuts and almonds
- Onions
- Red cabbage
- Seafood, such as shrimp and lobster
2. High-Fiber Foods
In addition to foods that are high in sulfur, eating food that’s high in fiber can increase your gas production. In combination with sulfur-rich foods, a high fiber intake may make it more likely that you’ll notice a rotten-egg smell when you pass gas. While fiber has a wide range of health benefits, it can cause excess flatulence. You may want to increase your intake to avoid passing gas.
Foods that are especially high in fiber include:
- Beans, nuts, and legumes
- Cruciferous vegetables (broccoli, cauliflower, Brussels sprouts)
- Leafy green vegetables (kale, collard greens, romaine lettuce)
- Whole grains
- Fruits
3. Bacteria in Your Gut
The odor of flatulence is derived from bacterial growth in the large intestine. This is normal. However, some people have gut flora that produce stronger odors. This may simply be due to individual differences, an underlying health condition, or dietary patterns.
4. Problems Digesting Carbohydrates
Gas forms during the digestive process. If you have trouble digesting carbohydrates, you might experience an increase in flatulence, as well as increased odors. Some of the most common causes of difficulty digesting carbohydrates include lactose intolerance, fructose intolerance, and eating certain high-sugar foods that are harder on the intestines.
5. Constipation
Constipation is defined as difficulty passing stool, typically fewer than three times per week. It often accompanies excessive gas and odors, including an eggy smell. There are many different causes of constipation, including but not limited to:
- Taking certain medications, such as antacids, anti-seizure medications, diuretics, calcium channel blockers, some antibiotics, and antidepressants
- Pregnancy
- Dietary choices
- Pelvic floor disorders
- Dehydration
- Celiac disease
- Inflammation
6. Medical Conditions
In rare cases, excessive gas that smells like sulfur may be a sign of a medical condition. Medical conditions that can affect the odor or frequency of your flatulence include:
- Infections
- Small intestinal bacterial overgrowth (SIBO)
- Inflammatory bowel disease (IBD)
- Irritable bowel syndrome (IBS)
- Bowel obstruction (which, very rarely, may be due to certain cancers)
When to See a Healthcare Provider
Gas that smells like rotten eggs typically isn’t a sign of a health problem. But you should consider seeing a healthcare provider if you have smelly, excessive, and/or persistent gas alongside symptoms like:
- Abdominal pain
- Blood in your stool
- Diarrhea
- Difficulty passing stool
- Fever
- Heartburn
- Nausea
- Oily or discolored stool
- Rectal pain
- Vomiting
- Weight loss
How to Reduce Smelly Gas
To cut back on smelly gas (and gas in general) there are a few steps you can take on your own. This often involves making lifestyle changes that lead you to swallow less air on a regular basis. You can:
- Take over-the-counter (OTC) medications for quick relief.
- Eat smaller meals.
- Eat more slowly.
- Steer clear of bubbly drinks.
- Avoid hard candy and gum.
- Quit smoking.
- Eat while sitting down.
- Eat fewer foods and snacks that tend to cause gas, such as sugar-free gum, high-fiber foods, and high-fructose foods.
Summary
Flatulence that smells like rotten eggs is common and is caused by eating foods containing sulfur. Sulfur is found in foods like meats and cruciferous vegetables. Other causes of flatulence that smell like rotten eggs are underlying gastrointestinal issues and a high-fiber diet. If the gas persists and occurs alongside symptoms like stool changes or pain, see your healthcare provider.
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
MedlinePlus. Gas.
Miękus N, Marszałek K, Podlacha M, et al. Health benefits of plant-derived sulfur compounds, glucosinolates, and organosulfur compounds. Molecules. 2020;25(17):3804. doi:10.3390/molecules25173804
Quagliani D, Felt-Gunderson P. Closing America’s fiber intake gap. Am J Lifestyle Med. 2016;11(1):80-85. doi:10.1177/1559827615588079
American Heart Association. Sound the fiber alarm! Most of us need more of it in our diet.
MedlinePlus Medical Encyclopedia. Gas - flatulence.
National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of constipation.
National Institute of Diabetes and Digestive and Kidney Diseases. Treatment for gas in the digestive tract. Last updated: June 2021.
By Laura Dorwart
Dr. Dorwart has a Ph.D. from UC San Diego and is a health journalist interested in mental health, pregnancy, and disability rights.
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