- The release of air or gas from the stomach or esophagus through the mouth. Eructation is usually caused by a buildup of air in the esophagus or upper part of the stomach when too much air is swallowed. This can occur when eating or drinking too fast, talking while eating, drinking carbonated drinks, chewing gum, smoking, or having an anxiety attack. Eructation may also be a side effect of certain medicines or a symptom of some gastrointestinal conditions and digestive problems, such as gastroesophageal reflux disease, gastritis, and stomach ulcers or infections. Also called belching and burping.