Flatulence: Gas buildup in the colon
Intestinal gas is typically caused by the fermentation of undigested food, such as plant fiber, in the colon. Gas can also form when your digestive system doesn't completely break down certain components in foods, such as gluten or the sugar in dairy products and fruit.
Other sources of intestinal gas may include:
- Food residue in your colon
- Changes in intestinal bacteria due to antibiotics or other medications
- Carbohydrate malabsorption, which can upset the balance of helpful bacteria in your digestive system
- Swallowed air that migrates to your colon
- Constipation — the longer food waste remains in your colon, the more time it has to ferment
Sometimes, gas indicates a digestive disorder, such as irritable bowel syndrome or lactose intolerance.
To prevent excessive gas, it may help to:
- Avoid the foods that affect you most. Common offenders include beans, peas, lentils, cabbage, onions, broccoli, cauliflower, bananas, raisins, whole-wheat bread, salads and carbonated drinks. If dairy products are a problem, try low-lactose or lactose-free varieties.
- Eat fewer fatty foods. Fat slows digestion, giving food more time to ferment.
- Temporarily cut back on high-fiber foods. Fiber aids digestion, but many high-fiber foods are also great gas producers. After a break, slowly add fiber back to your diet. Add products such as Beano to high-fiber foods to help reduce the amount of gas they produce.
- Eat slowly. Try to make meals relaxed occasions. Eating when you're stressed or on the run can interfere with digestion.
- Get moving. It may help to take a short walk after eating.
- Try an over-the-counter remedy. Products such as Lactaid or Dairy Ease can help digest lactose. Products containing simethicone help break up the bubbles in gas.
When to see your doctor
Bouts of excess bloating, belching and gas often resolve on their own. Consult your doctor if your symptoms don't improve with changes in eating habits or you notice:
- Severe, prolonged or recurrent abdominal pain
- Nausea or vomiting
- Bloody stools
- Weight loss
- Chest pain
These symptoms could signal an underlying digestive condition. Intestinal symptoms can be embarrassing — but don't let embarrassment keep you from seeking help. Treatment is available.
Apr. 23, 2011
See more In-depth
- Gas in the digestive tract. National Digestive Diseases Information Clearinghouse. http://digestive.niddk.nih.gov/ddiseases/pubs/gas. Accessed March 4, 2011.
- Living with gas in the digestive tract. American Gastroenterological Association. http://www.gastro.org/patient-center/digestive-conditions/gas-in-the-digestive-tract. Accessed March 4, 2011.
- Gas-related complaints. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/sec02/ch008/ch008d.html. Accessed March 4, 2011.
- Abraczinskas D, et al. Intestinal gas and bloating. http://www.uptodate.com/home/index.html. Accessed March 4, 2011.
- Picco MF (expert opinion). Mayo Clinic, Jacksonville, Fla. March 15, 2011.