Passing a lot of gas is usually normal and caused by swallowed air or high-fiber and gas-producing foods. See a doctor if it comes with pain or other symptoms.
Normal
People pass gas 14 to 23 times a day.
Causes
- Swallowed air.
- High fiber foods: beans, broccoli, onions.
- Carbonated drinks.
- Sugar alcohols.
- Lactose intolerance.
Reduce
- Eat slowly.
- Limit gas-producing foods.
- Walk after meals.
See a doctor
If gas comes with pain, bloating, weight loss, blood in stool or diarrhea.
How much gas is normal
The average person passes gas 13 to 21 times per day, according to the NIDDK. Gas comes from swallowed air and from bacteria fermenting carbohydrates in the colon. Gas is mostly nitrogen, oxygen, carbon dioxide, hydrogen and methane, and less than 1 percent includes odor-causing sulfur compounds.
- Foods that increase gas include beans, onions, broccoli, cabbage, whole grains, dairy (if lactose intolerant), sugar alcohols like sorbitol and carbonated drinks.
- Fiber increases gas initially as the microbiome adjusts.
- Constipation traps gas and increases bloating.
Reduce and see a doctor
Eat slowly, avoid gum and straws, track foods, and try a low FODMAP diet under supervision. Simethicone and alpha-galactosidase can relieve symptoms for some. See a doctor for gas with weight loss, blood in stool, persistent diarrhea, severe pain or fever. These could signal celiac disease, inflammatory bowel disease, SIBO or other conditions.
How much gas is normal
The average person passes gas about 14 to 23 times a day, producing about 0.5 to 1.5 liters, according to the NIH. Gas comes from swallowed air and bacterial fermentation of fiber and sugars. High fiber diets, beans, dairy, sugar alcohols and carbonated drinks increase gas.
Reduce and see a doctor
Eat slowly, limit gum and carbonated drinks, and try a food diary. Lactose intolerance, IBS, celiac disease and bacterial overgrowth may cause excess gas. See a doctor for gas with weight loss, blood in stool, severe pain or persistent diarrhea. Simethicone and alpha galactosidase products are sold over the counter.
Digestive causes
Gas is produced by fermentation of undigested carbohydrates. High FODMAP foods like onions, garlic, wheat and apples cause more gas in people with IBS. Lactose intolerance affects about 65 percent of adults worldwide, and fructose malabsorption another 30 to 40 percent. Swallowing air with chewing gum, straws and carbonated drinks adds.
Medical conditions and treatments
Celiac disease affects about 1 percent of the population and causes gas, bloating and diarrhea with gluten. SIBO can cause bloating and flatulence. Drugs such as acarbose, metformin and GLP-1 agonists cause gas. Probiotics have mixed evidence. A low FODMAP diet under dietitian guidance helps about 50 to 75 percent of people with IBS.
Based on data from the NIDDK and the American College of Gastroenterology
