Heartburn in the middle of the night can be caused by indigestion, gastroesophageal reflux, peptic ulcer and other diseases. 1. Indigestion: If you eat too many desserts, sweets, or spicy or irritating foods before going to bed, you may experience heartburn in the middle of the night. 2. Gastroesophageal reflux: If the patient suffers from gastroesophageal reflux, because the gastric fluid and duodenal fluid flow back into the esophagus, it may lead to esophageal mucosal damage, which may cause symptoms such as heartburn in the middle of the night. 3. Peptic ulcer: Peptic ulcer usually refers to chronic ulcers that occur in the stomach and duodenum. Due to the excessive secretion of gastric acid, duodenal ulcer patients are prone to the phenomenon of heartburn at night. It is recommended that patients with heartburn in the middle of the night should go to the hospital in a timely manner, under the guidance of the doctor to clarify the cause of the disease, and then take effective treatment.