My dentist told me to eat 2 servings of yogurt a day, when I have canker sores. This is suppose to help w/ the yeast problem. I've also prchased a toothpaste for canker sores, (rebrandt). Both of these have seemed to help me. I use to get cankersores all the time. There's also a medication that you can get from your Dr.. It's a clear liquid, it starts w/ a "L." That gave me alot of relieve. Good luck.