The causes of stomach acidity include improper diet, gastric and duodenal diseases and mental factors. 1. Improper diet: When eating too much food, spicy, cold, high starch, acidic or sweet food, it will promote a large amount of gastric acid secretion from the gastric sinuses, resulting in stomach acid. 2. Gastric and duodenal diseases: when there are gastroesophageal reflux disease, gastrinoma, gastric ulcer and duodenal ulcer, the gastrointestinal function will be changed, which will cause an increase of gastric acid secretion, acid reflux, nausea and other symptoms. 3. Mental factors: due to high mental tension or stressful situations, the nerves that govern the secretion of gastric acid cannot be well governed, which will lead to excessive secretion of gastric acid. When stomach acid occurs, you can use omeprazole, lansoprazole and other acid-suppressing drugs for treatment, and at the same time, you can use bismuth potassium citrate to protect the gastric mucosa, please follow the doctor’s instructions for the use of medication.