DefinitionGas, also called flatus or flatulence, is air in the intestine that is passed through the rectum. Air that is passed from the digestive tract through the mouth is called belching.Alternative NamesFlatulence (flatus)ConsiderationsGas is formed in the intestines as food is being digested. Gas can make you feel bloated, which may cause crampy or colicky abdominal pain.Common CausesGas can be caused by any of the following:AntibioticsEating foods that are difficult to digest, such as fiber. If you recently introduced fiber into your diet, having gas may be temporary. Give it a little time. Your body may adjust and stop producing gas.Eating foods that you cannot tolerate -- for example, if you have lactose intolerance and eat dairy productsIrritable bowel syndrome -- a chronic form of