I used to get canker sores, but then I started taking vitamins, particularly a multi-B, plus C and I've never had them since. My doctor recommended the multi-B, plus C supplement. The B also has a nice side effect of improving my complexion overall. For a quick cure, however, I used to put salt on them - it would burn like heck, but then the sore would go away the next day. I also think a crushed vitamin C tablet would be good.