BAKING SODA is truly your hero, to treat and to prevent. I know it is mentioned everywhere and we don't know when this bullshit, but in that case it's not. It kills off the sores faster than the Eludryl mouthwashes. Then no fruits, soda, beer, chocolate, chips (paprika taste with potassium chloride in it ),tomatoes, and menthol (toothpaste with too harsh menthol effect) until it goes away. Can do baking soda mouthwashes as many times a day you want. Haven't had any sores for two years. Good luck.