I have been on Prilosec for some time now. My ulcer was not caused by the bacteria, but by stress. However, most ulcers are caused by bacteria, and you should be tested for that bacteria. You may respond to Zantac. The prescription dosage is 150-300 mg. twice a day. Prilosec is once a day. But you need to be tested for the bacteria first. It is a blood test, but is only done in a few labs, so blood sample will probably have to be sent to another lab which will actually perform the test. You probably should be seeing a gastroenterologist for this problem. Best of luck.