Why Am I So Gassy? A Complete Guide to the Causes (and What Helps)

If you’ve been asking yourself why you’re so gassy lately, you’re far from alone. Gas is a normal part of digestion. Most people pass gas somewhere between 13 and 21 times a day, usually without thinking twice about it.

What sends people searching is a change. Maybe you’re gassier than you used to be, the smell is stronger, or it’s started to affect how comfortable you feel at work, at home, or out with friends.

Gas comes from two main sources. The first is air you swallow when you eat, drink, talk, or chew gum. The second is bacteria in your large intestine breaking down food your body didn’t fully digest. That fermentation produces gases like hydrogen, carbon dioxide, and methane. A small amount of sulfur compounds causes most of the smell.

Almost anything that changes what reaches your gut, how fast it moves, or which bacteria live there can change your gas. This guide walks through the most common causes, grouped by category. Each section gives you a short answer and links to a full article if you want to go deeper.

The Usual Suspects: Foods and Drinks That Cause Gas

Food is the most common cause of extra gas. It’s also the easiest to test. Many of the biggest triggers are foods people eat because they’re healthy, which is why gas often increases when someone starts eating “better.”

The main culprits are fermentable carbohydrates, often called FODMAPs. These are sugars and fibers your small intestine doesn’t fully absorb. When they reach your colon, gut bacteria feast on them and release gas. Carbonated drinks and habits like chewing gum add swallowed air on top.

Foods

Beans and lentils contain oligosaccharides, a type of sugar the body can’t break down on its own. Hummus brings the same compounds in a form that’s easy to eat in large amounts. Cruciferous vegetables like kale, broccoli, and cabbage contain both fermentable fiber and sulfur compounds, which can make gas smell stronger. High-protein diets can also change gas odor and lead to protein farts, especially when they rely on protein powders or bars with added sugar alcohols.

Drinks

Beer combines carbonation with fermentable carbs from grains, a reliable recipe for bloating. Coffee speeds up digestion and can stir up gas for some people. Oat milk contains fiber and added sugars that some guts don’t tolerate well. Sparkling water adds carbon dioxide directly. Kombucha is more complicated: it’s fermented and fizzy, and its effect on gas varies from person to person.

Chewing gum deserves a mention too. You swallow extra air with every chew, and many sugar-free gums use sugar alcohols that ferment in the gut.

Eating patterns

Big changes in how you eat can shift gas for weeks while your gut adjusts. Switching to keto changes which bacteria thrive in your gut. A plant-based diet usually means a big jump in fiber. Fasting can leave you gassy when you break the fast, especially if your first meal is large or rich.

Healthy Habits with Gassy Side Effects: Supplements That Cause Gas

Supplements are an often-overlooked cause of gas. Some pull water into the intestines, some feed gut bacteria, and many contain fillers or sweeteners that ferment. The good news is that the form and dose often matter more than the supplement itself. Many people can switch versions instead of giving it up.

Creatine can cause bloating and gas, especially during a “loading” phase or when taken in large single doses. Magnesium, particularly the citrate and oxide forms, draws water into the gut and can speed things along. Certain vitamins and minerals, along with gummy vitamins sweetened with sugar alcohols, can also leave you gassy.

Check the Label: Medications That Cause Gas

Many common medications list gas, bloating, or digestive changes as side effects. Some change how fast food moves through your system. Others affect how well you digest certain foods or which bacteria live in your gut.

Metformin, one of the most prescribed diabetes medications, is well known for causing gas and digestive upset, especially in the first weeks. GLP-1 medications like Ozempic, Wegovy, and Mounjaro slow how quickly your stomach empties. That can lead to gas, bloating, and sulfur-smelling burps.

Gas-X and other simethicone products are a little different. They don’t stop your body from making gas. They break up gas bubbles so the gas is easier to pass.

If you think a medication is behind your gas, talk with your doctor or pharmacist before stopping or changing it. There are often simple adjustments, like taking it with food or changing the dose or form. In the meantime, underwear made for medication side effects can help you feel more at ease.

When It’s More Than Diet: Health Conditions That Cause Gas

Sometimes ongoing gas, bloating, or stronger odor comes with a diagnosed health condition. These situations deserve real attention, both from your care team and from the people around you. Here’s how some of the most common conditions affect gas.

Bubble gut describes the gurgling, bubbling feeling of gas moving through your intestines. It’s often linked to food intolerances, IBS, or a stomach bug.

Irritable bowel syndrome (IBS) affects how sensitive the gut is and how quickly it moves. People with IBS often feel gas more intensely and may produce more of it. Air travel and social situations can be especially stressful, and some people find that alcohol affects IBS symptoms too.

Crohn’s disease and ulcerative colitis cause inflammation in the digestive tract. That can affect how food is absorbed and lead to more gas, bloating, and odor, especially during flares.

Endometriosis can cause endo belly, painful bloating and gas linked to inflammation and hormonal changes.

Alcohol gastritis is irritation of the stomach lining from drinking. It often shows up as bloating, burping, and upper-belly discomfort.

Lactose intolerance and celiac disease both cause gas when certain foods aren’t digested properly: lactose for one, gluten for the other.

Shreddies offers underwear designed with specific conditions in mind, including IBS, Crohn’s, colitis, celiac disease, lactose intolerance, gastritis, and diverticulitis. 

Gas During Recovery: Surgery and Medical Treatment

Gas after surgery or during treatment is common. It’s also uncomfortable at a time when you’re already dealing with a lot. Most surgery-related gas is temporary, but knowing what to expect helps.

During laparoscopic surgery, surgeons inflate the abdomen with carbon dioxide so they can see clearly. Some of that gas stays behind and can cause bloating and even shoulder pain for a few days. Anesthesia and pain medications also slow the gut, which lets gas build up. Here’s what helps with gas after surgery.

After gallbladder removal, bile flows differently, so fatty meals can cause gas and loose stools while your body adjusts. Men recovering from prostate surgery often have their own set of comfort needs.

Chemotherapy affects the fast-growing cells that line the gut and can disrupt gut bacteria. This sometimes leads to chemo belly, a mix of bloating, gas, and digestive changes. Learn more about what helps with gas during cancer treatment.

For recovery and treatment, see our post-surgery underwear and chemo underwear pages.

If you’re caring for someone

If you’re supporting a partner, parent, or friend through surgery or treatment, gas may be something they feel too embarrassed to bring up. A calm, matter-of-fact approach helps. So does checking in with their care team about diet and medication timing, and having comfortable clothing on hand that helps them feel at ease around visitors. Small comforts can make a real difference in how present and relaxed someone feels during recovery.

Blame It on Your Hormones: Gas Through Every Life Stage

Hormones play a bigger role in digestion than most people realize. Progesterone, for example, relaxes smooth muscle, including the muscles that move food through your gut. When digestion slows, gas has more time to build.

That’s why gas often increases during pregnancy, after giving birth, and during perimenopause, when hormone levels rise and fall unpredictably. Men see changes with age too. Digestion tends to slow, and some people produce less lactase over time, which makes dairy harder to digest.

For every life stage, explore our maternity, perimenopause, and menopause underwear, our guide to the best underwear for mature women, and underwear for older men.

Worst Possible Timing: Gas From Stress, Sleep, Travel and More

Your gut doesn’t operate on its own. It responds to stress, your schedule, how much you move, and even the air pressure around you. These situations explain why gas seems to show up at the worst possible moments.

Stress and the gut-brain connection

Your brain and gut are in constant communication. Stress and anxiety can speed up digestion, change gut bacteria, and make you swallow more air without noticing. That’s the science behind stress farts, and why nervous situations, like a big presentation or a first date, can come with an unwelcome side of gas.

Time of day

Gas often follows a daily rhythm. Some people wake up gassy because gas built up overnight and starts moving once they’re upright. Others notice it most at night, after a full day of eating. And yes, you can pass gas in your sleep.

Travel and altitude

Air pressure drops as you go higher, so the gas in your gut expands at altitude. That’s why flights and mountain trips often leave people bloated and gassy. Travel also disrupts routines, sleep, and diet, all of which affect digestion. Here’s how fart-filtering underwear can save your next trip, plus our picks for travel underwear.

Exercise

Movement helps gas pass, which is usually a good thing, though not always at a convenient time. During long runs, blood flow shifts away from the gut, which can cause cramping and gas, often called runner’s gut. Yoga poses that compress or twist the belly can also release trapped gas.

Work and public spaces

For many people, the hardest part of gas isn’t the physical discomfort. It’s worrying about it around coworkers, in meetings, or in close quarters. Working from home brings its own challenges, like constant snacking and less movement during the day. Here are some tips for managing gas odor in public.

When Gas Feels Like Something Else

Trapped gas can cause surprisingly severe pain, sometimes in places you wouldn’t expect. Gas in the upper intestine can press against the diaphragm and cause chest discomfort. Gas in other areas can radiate to your back or shoulders.

Most gas is harmless, but some symptoms deserve a call to your doctor. Reach out if gas comes with any of these:

Unexplained weight loss

Blood in your stool, or black, tarry stools

Fever, vomiting, or ongoing diarrhea

Severe, persistent, or worsening abdominal pain

A noticeable change in bowel habits, especially after age 50

Difficulty swallowing

If you have chest pain and aren’t sure it’s gas, especially with shortness of breath, sweating, or pain spreading to your arm or jaw, seek emergency care right away.

How to Reduce Gas: What Actually Helps

Because gas has so many possible causes, the best approach is a little detective work. These steps help most people find their triggers and feel better.

Keep a food and symptom log. Track what you eat, when you take supplements or medications, and when gas shows up. Patterns often appear within a week or two.

Slow down at meals. Eating quickly means swallowing more air.

Add fiber gradually. Going from low fiber to high fiber overnight is a common cause of gas. Increase slowly and drink plenty of water.

Take a short walk after meals. Gentle movement helps gas move through.

Ask about a low-FODMAP trial. A dietitian can guide you through it to pinpoint which carbs bother you most.

Review your supplements and medications. Your doctor or pharmacist may be able to suggest a different form, dose, or timing.

Address stress where you can. Breathing exercises, regular movement, and enough sleep all support the gut-brain connection.

Odor Control & Living Comfortably While You Figure It Out

Finding the cause of your gas can take time. Some causes, like a health condition, a needed medication, or recovery from surgery, aren’t things you can simply change. You can’t always control when gas happens, but you can control whether anyone else notices the odor.

Shreddies underwear is made with Zorflex® activated carbon cloth, built into a panel at the back of every pair. Activated carbon has an enormous surface area that captures odor compounds as gas passes through the fabric, so the smell is filtered before it reaches anyone else. Here’s a closer look at how flatulence filtering underwear works.

It’s important to know what Shreddies does and doesn’t do. Shreddies filters gas odor. It doesn’t stop gas from happening, muffle sound, or protect against leaks. There are no inserts or pads to replace. Shreddies looks and wears like everyday underwear, and you wash it just like the rest of your laundry. Our odor control underwear guide explains what to look for, and these dos and don’ts help you get the most from every pair.

For many people, that peace of mind makes it easier to focus on everything else: their health, their work, and the people around them.

Shreddies for Men

Everyday underwear with a secret talent

Boxers, hipsters, and briefs with built-in Zorflex® odor filtering. Big meeting, long flight, or game night, nobody needs to know.

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Shreddies for Women

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FAQs: All Things Gas

How much gas is normal in a day?

Most people pass gas between 13 and 21 times a day. More than that isn’t necessarily a problem. It’s usually a sign that something in your diet, routine, or health has changed.

Why does my gas suddenly smell worse?

Stronger-smelling gas usually comes from more sulfur compounds. Foods like eggs, meat, broccoli, cabbage, and garlic are common sources, as are protein supplements and some medications. A stomach bug or digestive condition can also change gas odor. If the change lasts more than a couple of weeks or comes with other symptoms, check in with your doctor.

Can gas be a sign of something serious?

Gas on its own is rarely serious. It’s worth seeing a doctor if gas comes with weight loss, blood in your stool, fever, persistent pain, or a lasting change in bowel habits.

Why am I gassier as I get older?

Digestion naturally slows with age, and many people produce less lactase, the enzyme that digests dairy. Hormonal changes, new medications, and lower activity levels can add to it.

Does fart-filtering underwear really work?

Underwear made with activated carbon, like Shreddies’ Zorflex® panel, filters odor as gas passes through the fabric. It doesn’t stop gas or sound, but it can keep odor from being noticeable to people around you.