My mother had recurring cold sores on her lips but also frequently had canker sores in her mouth. I used to have frequent canker sores but have never had a cold sore.

Even though it does seem a lot of high acid foods can trigger canker sores, mine were often associated with being over tired or stressed.

The tried and true treatment for us was to dab powdered alum (from the seasoning section of the grocery store) on the tip of a damp finger and then apply it to the canker or cold sore. There is a brief intense tingling and bitterness from the application but relief is instant and for us the sores were usually gone within a day or two. I have even used this for a huge ¾ inch by ¾ inch sore in my throat. I simply dampened a Q-tip, dabbed it in the powdered alum and applied to the spot. The pain was gone instantly and the sore was completely healed in three days.

I hope this will help your readers as much as it has helped me and my mother.

DEAR READER:
I have received several remedies for treating canker and cold sores. They have including everything from using L-lysine tablets, to eliminating peanuts and high acid foods to reducing stress. But by far, the most commonly recommended home remedy was crystallized or powdered alum. Alum is used in many applications including crystal deodorants, makeup and pickling.

I have chosen to print your letter because you have given thorough instructions, evidence that it works and also where it can be found.