Flatulence (Gas): Flatulance (gas) is a normal bodily function. Excess gas may be produced by swallowing excess air, problems in the breakdown of undigested foods, lactase deficiency, malapsorbtion problems, and bowel habits such as parasites, poor dietary fiber, cancer, diverticulitis, thyroid problems, narcotic and other drug use. Increased flatulence (gas) can often be treated with OTC medication and diet changes.