Moderate amounts of intestinal gas are a normal component of human physiology and digestion, but often times gas formation can become excessive. There are two primary causes of intestinal gas. The first, and least controllable, is the inhalation of excess air, especially when eating or drinking. The second cause is the gas that is produced as a by-product of digestion. Excess gas is produced when digestion is incomplete or impaired, when there is insufficient gut flora or “probiotics” in the large intestine, or when other microbes such as yeast or parasites are present in the GI tract.