Acid reflux in the stomach in the middle of the night may be caused by indigestion, gastritis, gastroesophageal reflux and other diseases. 1. Indigestion: eating too much food, food accumulation is prone to increased secretion of gastric acid, which can lead to the symptoms of acid reflux in the middle of the night, you can take gastric tablets, omeprazole acid suppression drugs for treatment. 2. Gastritis: this kind of people due to excessive secretion of gastric acid, so in the middle of the night there can be symptoms of acid reflux in the stomach, you can take omeprazole and other acid suppression drugs, bismuth potassium citrate and other gastric mucosa protection drugs for treatment. 3. Reflux esophagitis: this kind of people can have symptoms such as acid reflux, heartburn, nausea and vomiting, etc., which can be treated by taking omeprazole and domperidone. The above medications should be applied under the advice of a doctor, and timely consultation is recommended.