How soon can an ulcer form from h plyori?

Ulcer: I don't think there is any way to predict the timing of how quickly a gastric ulcer can develop whether from H. Pylori or other causes. I will say that it isn't immediate. An ulcer is an erosion of, in this case, the stomach lining. One part of the problem in answering your question is that no one can say when you got exposed to H. Pylori and if it is the cause of the ulcer.