The Mayo Clinic Health Letter suggests temporarily avoiding certain foods to help identify the cause of the gassiness. The usual suspects are:

-- Dairy products: Lactose, a sugar found in dairy foods, commonly causes gas that may be helped by nonprescription products such as Lactaid or Dairy Ease.

-- Onions, radishes, cabbage, celery, carrots, Brussels sprouts, broccoli, cauliflower and legumes such as dried peas and beans. Beano, or other products containing simethicone may help.

-- Prunes, grapes, apples and apricots, as well as juices made from them, may contain a lot of fruit sugar which can cause gas.

-- High-fiber foods often are linked to gassiness, but it's usually the amount that causes the problem. Cut down and gradually increase to identify the tolerable amount.

-- Some sweeteners, including Sorbitol, mannitor and xylitol -- used in sugar-free candies -- can cause diarrhea in some people.

-- Carbonated or sparkling drinks and some fatty food such as fried items also can cause gas and may be avoided.