What causes gas?

Odor is caused by traces of skatole, indole, and compounds containing sulfur.

These gases are not present in everyone, but when they are present, they come from bacteria in the colon breaking down carbohydrates. We know of no way to modify the presence or amount of these gases.

Abdominal discomfort and bloating, thought to be caused by too much gas, are some of the most frequently encountered gastrointestinal complaints. However, the basic problem underlying complaints of bloating and distention is not too much gas, but is usually the increased sensitivity of the bowel wall to distention in some people.
Patricia Raymond, MD
Everyone passes about two liters of gas per day; it’s a problem when it troubles you. Air swallowing causes non-smelly gas, and poorly fitting dentures, drinking through straws, and carbonated beverages contribute.

Smelly gas comes from bowel bacteria composting unabsorbed foods and producing that raw egg smell. Record a food/gas diary to determine which foods cause the gas, and consider activated charcoal tablets to absorb the gas (caution: may absorb your medications too!).
Judy Caplan
Nutrition & Dietetics

There are many causes of gas. Sometimes it is due to not enough fiber in the diet. Then when you eat high fiber foods that you are not used to, you tend to develop gas. The extra fiber is the culprit. Instead of staying away from high fiber foods, you need to eat them more frequently so your body adjusts. Fermentable sugars called oligosaccharides can also cause gas. Certain individuals are allergic to these.

Continue Learning about Digestive Health

60 Minutes to a Healthier Colon
60 Minutes to a Healthier Colon
One in three adults will get colon polyps, but the odds drop to one in four if you do this for just 1 hour each week: exercise. Any activity will do....
Read More
How can a polyp turn into colon cancer?
Aurora Health CareAurora Health Care
Most colon cancers arise from polyps, which are growths on the lining of your colon. These polyps ar...
More Answers
5 Foods for Healthy Digestion
5 Foods for Healthy Digestion5 Foods for Healthy Digestion5 Foods for Healthy Digestion5 Foods for Healthy Digestion
Reach for these when your tummy rumbles.
Start Slideshow
The Surprising Food That Might Be Making You Bloated
The Surprising Food That Might Be Making You Bloated

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.