Acid in the mouth, also known as gastric acidity, is a common digestive symptom, not always a stomach problem. When there is too much acid in the stomach, the acidic secretions will irritate the gastric mucosa, causing panic acid and giving people a feeling of heartburn. There are many reasons for excessive stomach acid and acidity, and there are two main ones: First, physiological acidity. When mental tension, overwork and poor emotion, the cerebral cortex is dysfunctional and cannot well govern the nerves of gastric acid secretion, prompting an increase in gastric acid secretion. Improper diet, such as too sweet, too salty, too spicy, too acidic, too cold, too hot food can stimulate the increase in gastric acid secretion. And certain coarse grains, sweet potatoes, potatoes, etc. contain a lot of starch, sugar, acid, etc., will stimulate the stomach to produce a lot of stomach acid, and moreover, the food that is not easy to digest, the remaining sugar fermentation in the stomach and intestines, but also to induce pantothenic acid. Second, pathological acid flooding. Chronic gastritis, gastric or duodenal ulcer, etc., can contribute to the increase of stomach acid, often appearing panic acid.