Midnight flatulence is associated with indigestion, cold in the abdomen, and pyloric obstruction. Indigestion will not be accompanied by symptoms of prolonged food emptying time, and going to bed directly after eating may lead to a feeling of stomach distention in the middle of the night. Mainly because after sleeping, the stomach peristalsis will be relatively slow, and the food in the stomach is not able to be expelled, so a large amount of gas is released in the stomach, and the stomach becomes distended in the middle of the night. Some people do not pay attention to keep their abdomen warm when they sleep in the middle of the night, or even sleep under the air conditioner. When the abdomen is attacked by cold, there will be stagnation of gas and therefore bloating in the middle of the night. Pyloric obstruction will cause food not to be discharged into the duodenum, and the food ingested during the day will be retained in the stomach in large quantities, and at night, due to the fermentation of food, resulting in increased gastric pressure, not only will there be midnight gastric distention, but even nausea and vomiting.