First, chronic gastritis, which is a common and frequently-occurring disease, is characterized by pain in the upper abdomen, belching and abdominal distension, loss of appetite, indigestion, nausea and vomiting, and repeated bleeding. Chronic gastritis is harmful, which can lead to pathological changes in the stomach itself, and other diseases can lead to physical weakness of patients.

Second, acute simple gastritis, which can be divided into four categories: acute corrosive gastritis, acute erosive gastritis, acute simple gastritis and acute gastritis. Among them, simple gastritis and acute diffuse gastritis are the most common and frequently-occurring diseases, and the typical manifestations are abdominal cramps, diarrhea and nausea, loss of appetite, fever and dehydration, etc., and serious phenomena such as hematemesis, shock and acidosis may occur.

Third, acute suppurative gastritis, acute suppurative gastritis is caused by gastric ulcer and chronic gastritis, which damages the gastric mucosa and invades the stomach wall, causing acute upper abdominal pain, nausea, vomiting and so on.

Fourth, non-ulcerative dyspepsia, non-ulcerative dyspepsia is a functional stomach disease, and its clinical manifestations mainly include dull pain in the upper abdomen, acid reflux, persistent hiccups and so on.