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For two years I have been using a product called Debacterol which I have found to be most effective.  One quick application, and within a few seconds the pain is gone for good.  It stings like crazy for about 5 seconds, but then it stops and doesn't come back.  The canker sore heals within a few days with no more pain.

Apparently it is not sold directly to patients.  It is marketed to dental offices and pharmacists.  Go to www.debacterol.com for a description.

It is sulfuric acid and sulfonated phenolics in aqueous solution (I got that from the label.)  Basically, it cauterizes the ulcer.  

I am assuming that gluten cannot exist in sulfuric acid, so I have not contacted the company to see if it is GF.  The amount needed is miniscule; a tiny bottle (the size of those free perfume samples at department stores) has lasted me 2 years and there is a lot left.  It wasn't cheap; this little bottle cost over $30.00.  I drove to a dentist's office in Hugo, MN to get it, and they sold it to me over the counter.  

In my lifelong battle with canker sores, this has been far and away the best treatment for them. (I have no personal connection to this company.)

Barbara 
MN

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