Ulcers you mean cankers as well right? Not sure if this is a cure but I used to get them all the time until I used hydrogen peroxide as a mouthwash. Make sure you mix it 50/50 with water. Don't swish it straight. When I started using H202 it wasn't even for cankers but I notice it's been over a year and I've never had a canker again. I used to get them quite frequently especially after eating things with tomato sauce.