Chronic gastritis is often characterised by persistent [[vomiting|vomiting]] of variable frequency and appearance. The underlying cause is unknown but chronic gastritis can be classified into one of four types according to its histological appearance. | Chronic gastritis is often characterised by persistent [[vomiting|vomiting]] of variable frequency and appearance. The underlying cause is unknown but chronic gastritis can be classified into one of four types according to its histological appearance. |