Hi. My PWP husband does not suffer from canker sores, but I do, and it always tells me I'm stressed or coming down with something (usually the former). Someone on this List recommended "Prescription for Nutritional Healing" and for canker sores it recommends acidophilus (which I got at a small health food store) and an anti-oxidant which I got from AARP, and several other things which I haven't bought (trying not to spend too much). I think the book's recommendations have helped me, but by all means check it for yourself and check with your dr. Best wishes, Delda White ([log in to unmask]).