newbeymum, i used to have mouth sores very often. nawala lang when i learned to eat A LOT of fruits and vegetables, and cut down drastically of meat, fats, & baked food. very acidic pala ang dugo ko dati. another cause of acidity is the way food is cooked. food that is baked, roasted or deep fried makes food acidic in the stomach.
dati rati i would fight a cold or sore throat by drinking a lot of salabat and taking mega doses of Vitamin C. Then I always had mouth sores afterwards. yun pala ginger is acidic and of course Vitamin C is acidic.
now that my blood pH is always somewhere neutral most of the time, wala na akong problema sa mouth sores.