Intestinal gas, or air in the digestive tract, is usually not noticed until we burp or pass it rectally (flatulence). The entire digestive tract, from the stomach to the rectum, contains intestinal gas as the natural consequence of swallowing and digestion.
In fact, certain foods, such as beans, are not fully broken down until they reach the large intestine (colon), where bacteria act on (ferment) them.
Excessive intestinal gas sometimes indicates a digestive disorder, but everyone passes gas several times daily, and occasional burping or belching is normal.
Excess upper intestinal gas can result from swallowing more than a usual amount of air, overeating, smoking or chewing gum. Excess lower intestinal gas can be caused by eating too much of certain foods, by the inability to fully digest certain foods or by a disruption in the bacteria normally found in the colon.
Foods that cause gas in one person might not cause it in another. Common gas-producing foods and substances include:
Excessive intestinal gas — belching or flatulence more than 20 times a day — sometimes indicates a disorder such as:
By itself, intestinal gas rarely indicates a serious condition. It can cause discomfort and embarrassment, but it's usually just a sign of a normally functioning digestive system. If you're bothered by intestinal gas, try changing your diet.
However, see your doctor if your gas is persistent or severe, or if it's associated with vomiting, diarrhea, constipation, unintentional weight loss, blood in the stool or heartburn.