What Causes Gas?

Gas that collects in the digestive tract (esophagus, stomach, small and large intestines) is made up from these common sources, such as eating certain foods, swallowed air, medicines and supplements and certain medical conditions.

Eating Certain Foods

The small intestine does not digest and absorb some carbohydrates (sugars, starches and fibers) found in many foods because it lacks certain enzymes needed to do so. This undigested food then passes into the large intestine, where normal, harmless bacteria break down the food, producing hydrogen, carbon dioxide and, in some people, methane. This is what’s known as flatulence, and these gases will eventually exit through the rectum.

Foods that cause gas in one person may not cause gas in another. For instance, some bacteria in the large intestine can destroy the hydrogen that other bacteria produce. Therefore, some people have more and others have less gas.

Swallowed Air

Air swallowing (aerophagia) occurs every time we eat or drink. Eating or drinking rapidly or drinking through a straw can cause excess air to be inhaled. Chewing gum, smoking or wearing loose dentures can also increase your intake of air.

Most swallowed air leaves the stomach through burping or belching a gas made up of nitrogen, oxygen and carbon dioxide. The remaining gas moves into the small intestine, where it’s partially absorbed. Then a small amount travels into the large intestine, where it is released through the rectum.

Medicines and Supplements

Two side effects of prescription or nonprescription medicines or dietary supplements are bloating or gas. These include aspirin, diarrhea medicines, narcotic pain medicines, fiber supplements, bulking agents, multivitamins and iron pills.

If you are taking medicines or supplements and symptoms of gas occur, consult your doctor about taking Phazyme®.

Certain Medical Conditions

Other causes of gas may include surgery, changes in hormone levels and medical conditions such as gastrointestinal disorders and food allergies. If you experience gas for these reasons, it’s best to report this discomfort to your healthcare provider.