Bloating & Gas

The presence of gas in the small intestines and colon is a normal event that results from a combination of air swallowing and the formation of gas (by bacteria) in the colon. This gas must be eliminated either by belching via the mouth or by the passage of flatus via the anus, more commonly referred to as burping and farting (or passing gas).


Belching can result from one or more of the following:

  • ingesting air when eating and drinking, especially if using poorly fitting dentures
  • eating rapidly
  • drinking fizzy beverages
  • Illustration of a man sitting at a table and feeling full after eating.

Air swallowing can also be an unconscious habit, resulting in frequent and persistent belching. Being alert to the habit of air swallowing is the first step in relieving this problem.

Much of the air that is swallowed is expelled by belching, but a percentage makes its way through the small intestine —the bowel wall absorbs air slowly— and is passed as flatus.

Flatus also results from the breakdown of undigested food in the colon by bacteria. Cabbage, broccoli, baked beans, onions, bran and other high fiber containing fruits, grains and vegetables are especially likely to cause excessive gas production and thus excessive flatus.

In addition, some individuals lack the enzyme responsible for digesting lactose in the small intestine. (Lactose is a sugar present in dairy products, such as milk, cheese, cottage cheese, yogurt, ice cream, plus more.) These individuals frequently complain of excessive gas after drinking milk or consuming dairy produce.


Excessive intestinal gas may cause abdominal discomfort and bloating. Some recommended methods to help minimize belching and flatus include:

  • decreasing dietary fiber intake
  • decreasing or avoiding dairy produce, or drinking lactase-fortified milk
  • chewing slowly and completely
  • avoid chewing gum and candy
  • avoiding fizzy drinks

Wearing well-fitting dentures may also provide some relief. Patients with irritable bowel syndrome appear to be especially sensitive to the effects of excessive intestinal gas and often complain of bloating which increases as the day progresses or after meals. Lying down tends to decrease bloating, at least partially, in such persons.

It should be noted that poor posture and/or poor abdominal wall tone may also contribute to bloating.