Diet and stop smoking to treat gastritis .. Avoid caffeine and commit to a diet of boiled potatoes, boiled rice, spaghetti, bananas, cakes

Depending on the situation and available treatments:
1- Diet: Avoid caffeine (coffee, tea, cola, chocolate, coca) and any foods that may irritate your stomach (spices, sour foods) including tomatoes, fruits and yogurt. Cakes.
2- Smoking: Smoking should be stopped.