Gastritis is divided into two types: acute gastritis and chronic gastritis. The main cause of acute gastritis is bacterial or viral infection, with primary symptoms including abdominal pain, nausea, vomiting, and fever. Chronic gastritis is mainly caused by the digestion of the stomach itself due to stomach acid and pepsin. Its main cause is closely related to infection by Helicobacter pylori, with primary symptoms being upper abdominal distension, belching, acid reflux, nausea, vomiting, heartburn, poor appetite, and indigestion. For acute gastritis, a routine blood test is necessary to confirm the diagnosis. For chronic gastritis, a gastroscopy and a carbon-14 breath test are required to determine if there is an infection with Helicobacter pylori, which are the main examinations.