Occasional flatulence is caused by indigestion of the food eaten, but prolonged flatulence and nausea should be alerted to chronic gastritis and gastric ulcer. Flatulence occurs because the stomach and intestines are not able to digest food and produce gas in the body. Eating food that is not easy to digest or food that has strong irritation will affect the digestion of food when it enters the body. Some people will show abdominal flatulence, which has nothing to do with diseases and needs to be improved through life care. Long-term flatulence and nausea are directly related to chronic gastritis and gastric ulcers. Patients with chronic gastritis and gastric ulcers are not able to digest food after ingesting it and the peristaltic function of the intestines and stomach will be affected, which will cause flatulence and nausea after eating food.