If you have an upset stomach at night and feel better in the morning, consider it to be related to inflammation of the stomach, duodenal bulb ulcer, gastroesophageal reflux and other diseases. 1. Inflammation of the stomach: If you are fine during the day but feel sick at night, it is related to gastritis. Eating too much food during the day may increase the burden on the digestive system, leading to bloating and stomach pain at night. Especially at night, vagus nerve excitation and visceral hypersensitivity lead to increased discomfort. 2. Duodenal bulb ulcer: Peptic ulcers, such as duodenal bulb ulcer, the typical symptoms of patients are abdominal pain during fasting, pain at night, pain in the early hours of the morning, and the symptoms can be relieved after meals. 3. Gastroesophageal reflux: Gastroesophageal reflux, such as reflux gastritis, can lead to food reflux when lying in bed at night with increased gastric pressure, which can easily cause stomach discomfort. Reflux usually does not occur during the day, so it is fine during the day. If you often have stomach discomfort at night, it is recommended that you go to the gastroenterology department of the hospital to clarify the cause and standardize the diagnosis and treatment.