Passing gas is normal, and most people do it far more often than they realize. Healthy adults pass gas up to 25 times a day. If you’re noticing more than that, or your gas has become uncomfortable, smelly, or disruptive, the cause usually traces back to what you’re eating, how you’re eating, or how your gut processes food.
What Counts as Excessive Gas
There’s no strict clinical cutoff for “too much” gas because the baseline varies so widely. Someone passing gas 15 times a day is perfectly normal. So is someone closer to 25. What matters more than the number is whether your gas has changed noticeably, whether it comes with bloating or pain, and whether it’s interfering with your daily life. A sudden increase from your personal norm is more meaningful than any single number.
Foods That Produce the Most Gas
The biggest driver of intestinal gas is a group of carbohydrates your small intestine can’t break down. These short-chain carbohydrates (sometimes called FODMAPs) pass through undigested until they reach the large intestine, where bacteria ferment them. That fermentation is what produces gas as a byproduct. Your small intestine also draws in extra water trying to move these undigested molecules along, which is why gas-heavy meals often come with bloating or loose stools too.
The main categories of these hard-to-digest carbohydrates include:
- Soluble plant fibers (oligosaccharides): Found in beans, lentils, onions, garlic, and many wheat products. These are the classic “gassy” foods.
- Lactose: The sugar in dairy products. If your body doesn’t produce enough of the enzyme to break it down, dairy ferments in the gut instead.
- Fructose: The sugar in fruit, honey, and many sweetened beverages. Some people absorb fructose poorly, especially in large amounts.
- Sugar alcohols: Found in sugar-free gum, candy, and some fruits. Common names on labels include sorbitol, mannitol, and xylitol.
If your gas is worse after specific meals, keeping a simple food diary for a week or two can reveal patterns quickly. The connection between a particular food and gas usually shows up within a few hours.
Swallowed Air Adds Up Fast
Not all gas starts in the gut. A surprising amount comes from air you swallow without realizing it, a habit called aerophagia. Specific behaviors that increase swallowed air include eating too fast, talking while eating, chewing gum, sucking on hard candy, drinking through straws, drinking carbonated beverages, and smoking. Swallowed air tends to cause more burping than flatulence, but some of it travels all the way through the digestive tract and exits the other end.
If your gas is worse during stressful periods, stress-related mouth breathing and fast eating may be contributing more than you’d expect. Slowing down at meals and cutting out gum or carbonated drinks for a few days is one of the simplest experiments you can try.
Lactose Intolerance Is Extremely Common
About 60 percent of adults worldwide stop producing enough of the enzyme needed to digest milk sugar as they mature. The rates vary dramatically by ancestry: as low as 2 percent in Denmark, as high as 100 percent in parts of Africa. In the United States, up to 75 percent of African Americans and American Indians and 90 percent of Asian Americans are lactose intolerant. Many people with mild intolerance don’t connect their gas to dairy because they’ve always eaten it and the symptoms seem “normal.”
If you suspect dairy is the issue, try eliminating it completely for two weeks and then reintroducing it. The difference is usually obvious within days.
Why Some Gas Smells Worse Than Others
Most intestinal gas is actually odorless, made up of hydrogen, carbon dioxide, and sometimes methane. The smell comes from sulfur-containing compounds that make up a tiny fraction of each release, on average just 50 parts per million. Certain gut bacteria convert hydrogen into hydrogen sulfide (the rotten egg smell), methanethiol (rotten cabbage), and dimethyl sulfide (garlic-like). High-sulfur foods like cruciferous vegetables, eggs, and meat tend to feed these bacteria and produce more pungent gas. If the volume of your gas hasn’t changed but the odor has gotten worse, your diet or your gut bacteria have likely shifted.
Medical Conditions That Increase Gas
When dietary changes don’t explain the problem, a few conditions are worth considering. Small intestinal bacterial overgrowth (SIBO) occurs when bacteria that normally live in the large intestine colonize the small intestine, where they ferment food prematurely. This can cause excessive gas, bloating, and diarrhea because the breakdown products of that bacterial digestion irritate the intestinal lining.
Gastroparesis, a condition where the stomach empties too slowly, can also contribute. When the muscles of the stomach don’t contract properly, food sits longer than it should before moving into the small intestine. This leads to bloating and can alter how food is digested downstream. The vagus nerve, which controls stomach contractions, is often involved. Diabetes is one of the more common causes of this nerve damage.
Celiac disease, inflammatory bowel disease, and pancreatic insufficiency can all disrupt normal digestion enough to increase gas production. These conditions typically come with other symptoms like persistent diarrhea, weight loss, or abdominal pain rather than gas alone.
Over-the-Counter Options
Two common products work in completely different ways. Products containing alpha-galactosidase (sold as Beano) supply an enzyme that helps break down the fermentable carbohydrates in beans, bran, and certain vegetables before gut bacteria get to them. You take it with the first bite of a problem food. Clinical trials have shown significant improvement in gas symptoms compared to placebo when used this way.
Simethicone (sold as Gas-X) works mechanically by breaking up gas bubbles already in the gut, making them easier to pass. It can help with the feeling of pressure or bloating, but research has not shown a clear benefit for reducing the actual amount of flatulence. It’s better for comfort than for prevention.
Neither product addresses an underlying cause. If your gas is persistent and not clearly tied to diet, they may offer temporary relief without solving the problem.
When Gas Signals Something Else
Gas by itself, even a lot of it, is rarely a sign of serious disease. But gas paired with certain other symptoms warrants a visit to your doctor: abdominal pain that doesn’t resolve, unexplained weight loss, blood in your stool, persistent diarrhea or constipation, or fever. A sudden change in your gas patterns with no obvious dietary explanation is also worth mentioning, especially if it persists for more than a few weeks.