I personally would cure gastritis with nutrition instead of medication, because medications have the tendency to irritate the digestive tract, etc... Gastritis actually happens with someone doesn't have enough vitamin B12, zinc, and probiotics (and if someone's pH level is too low: high acidity in the body). get your nutrient levels for vitamin B12 and zinc checked out. the doctor/nurse will take a blood test to see if you're low in either of them. also, make sure you're eating healthy ALKALIZING foods!
Youtube these doctors for more information:
Dr. Jonny Bowden
PS: google how a deficiency in vitamin B17 causes cancer!