I started getting canker sores more frequently when I moved to Florida (out of there now). The doctor suggested taking 400 mg of Vitamin E at least once a day. This makes your skin thicker and thus alleviates the potential for canker sores. Make sure you are eating plenty of vegetables each day, to include raw carrots. Stress may also be a factor so try to exercise at the gym or run, or walk, or swim. Get plenty of sleep (8 hours per day should do it). Anyway, hopefully this helps. Good Luck!!