Avoiding milk and milk products cured my canker sores. Both my mother and I suffered from sores in our mouths and we had tried many different remedies hoping to prevent them. Mom discovered that if she reduced her milk intake, she got fewer sores. Now, we both drink only soy milk and have been canker-free for years. Soy ice creams are getting better and better, too. I occasionally have some regular cheese and this doesn't seem to cause any problems. Cheese made from soy is still pretty awful.