The ingestion of air, whether intentionally or otherwise, is called aerophagia. The air entering the body contains nitrogen and oxygen gas. This gas will be pushed upward by the stomach into the esophagus and out of the mouth in the form of saltpeter. Gas in the human body is generally formed from the digestive process of food or when there is air swallowed through the mouth. Air can enter the body if you talk while eating, chewing gum, sucking candy, eating too fast, or smoking.
