More commonly known as canker sores, recurrent aphthous stomatitis (RAS) can be quite a nuisance. Because the sores are associated with systemic inflammation, I believe that they can be preventable, and I have seen this first-hand in patients. Today I want to cover three important ways you can help prevent them. I also want to tell you about a surprising at-home treatment that has proven to be more effective than prescriotion medication.