Symptoms of IBS: Excessive Gas Or Flatulence

Reviewed by: HU Medical Review Board | Last reviewed: May 2020 | Last updated: January 2023

Many people with IBS experience excessive gassiness. It can be a major source of embarrassment and discomfort. And the resulting stress can have a negative impact on the quality of life and productivity.

It is not clear why IBS causes excessive gas. Most people with IBS actually do not produce more gas but are more aware of normal amounts of gas.

Treating excessive gas is hard because no single treatment works for everyone. Foods that give someone else gas may not bother you. And therapies that relieve gas for someone else may not help you. Talk to your doctor to determine the right treatment for you.

What causes excessive gas?

Passing gas around 13-21 times per day is normal. Burping occasionally during and after meals is also normal. You should talk to your doctor if your gas symptoms bother you or change suddenly, or if you also have other IBS symptoms.1

The amount of gas you produce depends on your diet and other individual factors. There are two main sources of gas in the intestine:2

Air swallowing

It is normal to swallow a small amount of air when eating and drinking. You may swallow more air if you eat quickly, gulp liquids, chew gum, or smoke. Burping removes most air, but a small amount may pass from the stomach to the small intestine.

Bacterial production

Your colon contains bacteria that support healthy bowel movements. However, some carbohydrates (sugars, starches, and fibers) are not completely digested in the stomach and intestines. These foods must be broken down by bacteria in the colon. During this process, bacteria produce odorless gases like carbon dioxide and methane and small amounts of smelly components like sulfur.

Why does IBS cause excessive gas?

Many people with IBS feel they pass too much gas or burp too frequently. But most people bothered by gas symptoms do not actually have more gas in the intestine. Instead, they are more sensitive to normal amounts of gas. The medical term for this increased sensitivity is “visceral hyperalgesia.”3

We do not know why IBS causes increased sensitivity in the intestines. One theory is that nerves carrying messages from the bowel are hyperactive in people with IBS. This causes normal amounts of gas to be more painful. Some people feel better with medications that decrease pain perception in the intestines.2

Another possibility is that IBS causes more severe food allergies. Many foods worsen IBS gas symptoms, especially ones that contain specific carbohydrates called FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols). FODMAPs are found in wheat, barley, milk, and certain fruits and vegetables.2

How is excessive gas treated?

There are many treatments for excessive gas. It sometimes takes a while to figure out what works for you. So it is good to communicate often with your doctor about your symptoms and stressors. And it is a good idea to use a daily diary to monitor your diet and bowel movements.

The first treatment is often changing your diet to avoid foods that aggravate gas. Talk to your doctor if you want to try avoiding certain foods. They can give advice on what to limit and how to get enough nutrients.2

Many people with IBS respond well to a low FODMAP diet.4 So your doctor may recommend a diet low in FODMAPs. Here are some examples of high FODMAP foods:5

  • Grains: wheat, rye, and barley
  • Fruits: apples, apricots, blackberries, cherries, dates, grapefruits, mangos, pears, and watermelons
  • Vegetables: artichokes, asparagus, cauliflower, garlic, leeks, mushrooms, and onions
  • Dairy: coconut milk, ice cream, milk, cheese, soy milk, and yogurt
  • Proteins: most beans, legumes, and processed meats
  • Beverages: high-fructose containing sodas and juices

However, prolonged FODMAP elimination can be unhealthy. So your doctor may methodically phase these foods back into your diet to determine which ones you can tolerate. This will create a personalized low-FODMAP diet that works for you.

There are also over-the-counter medications that may reduce bothersome gas. Products that contain simethicone (such as certain antacids) are widely used to relieve gas. And products that contain activated charcoal are also often used to reduce gas discomfort.2

Many prescription drugs are also available that may treat IBS gas. They are usually recommended only if diet changes do not work. Probiotics and antibiotics are also sometimes used to support intestinal bacteria that produce less gas.3

Treatment is usually best with an approach that combines diet and lifestyle changes, exercise, and medications. Talk to your doctor to find the right combination of treatments for you.

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