Hi Imabeliever...you are so right. My husband has been using an SLS free toothpaste for probably at least 6 months or more and has not had another canker sore and that's huge for him. He used to get one about once or twice a month. Guaranteed if he bit the inside of his mouth and then he'd have it for a week or so. I think he did bite the inside of his mouth recently and got a bit of a sore that is likely, regardless of whether you are prone to canker sores. It was sore for a day or two but never turned into a full blown canker sore so I'm convinced. Oh and great advise with the vitamin C. I'll have to keep that in mind. So funny that we have so many things at our disposal but are so ingrained to think of drugs that we need to remember these simple things. Thanks.