Gastric acid reflux in the middle of the night is caused by the patient being in the recumbent position and sleeping state. During the sleeping state, the body’s parasympathetic nerves are excited, resulting in relaxation of the lower esophageal sphincter, and the gastric acid secreted in the recumbent position tends to reflux through the lower esophageal sphincter, which leads to acid reflux at night. It is most commonly seen in GERD, but diseases such as gastric ulcer and chronic gastritis cannot be excluded. Gastroscopy, ultrasound and other tests are needed to clarify the cause, and then pharmacological and behavioral treatments are given for specific diseases. Common diseases and treatments 1, GERD: GERD can appear as acid reflux and heartburn, mostly seen 1 hour after meals, symptoms can be more pronounced when lying down, bending over or coughing, and can also occur after sleeping. It is recommended not to eat within 3 hours before bedtime and to keep the head elevated 15-20 cm when sleeping. In severe cases, oral acid suppressants, such as omeprazole, can be taken under medical supervision; 2. Gastric ulcer: abdominal pain is most common, but indigestion symptoms such as acid reflux and belching, nausea and vomiting also exist, and the disease is easily complicated by upper gastrointestinal bleeding and perforation. Most patients are usually relieved by non-surgical treatment, such as diet adjustment, taking drugs such as acid suppressants and anti-H. pylori drugs, etc. When complications such as gastric bleeding and perforation occur, surgical treatment is required; 3. Chronic gastritis: chronic gastritis lacks specific symptoms, but there are also abdominal discomfort, decreased appetite, acid reflux, nausea and other manifestations. It is mainly treated by adjusting the diet, using proton pump inhibitors and antibacterial drugs. Precautions should also pay attention to a light and easy-to-digest diet, avoid spicy and stimulating diet, moderate exercise, eat less and more meals to reduce the occurrence of gastrointestinal diseases.