Gastric acid is a digestive fluid produced by the stomach. It primarily consists of hydrochloric acid, which helps break down food and kill harmful bacteria. This acidic environment is essential for activating digestive enzymes and facilitating the absorption of nutrients. The production of gastric acid is regulated by the body in response to food intake. When you eat, the stomach releases this acid to aid in digestion. Conditions like gastroesophageal reflux disease (GERD) can occur when there is an imbalance in acid production, leading to discomfort and other health issues.