No SLS, but still problems
When I changed from a typical toothpaste to Squigle a few years ago, my canker sores went way down. After a couple years, I ran out of Squigle and bought a tube of this Rembrandt product because I could get it locally. Within a couple weeks, I had five active canker sores in my mouth at once. It was the worst I had ever seen in my life. I finally thought to try removing the toothpaste, even thought it has no SLS. So I started brushing with just water. Within 48 hrs, 2 of the sores were healing. Within another 48hrs, they were all healing. I went back to Squigle and I have not had a problem since (a couple months). If this product doesn't work for you, try Squigle (also available on Amazon). If you read their website, they suggest that there are several classes of materials that may lead to canker sore problems including detergents (like SLS), bleaches (peroxides), etc. For me, this product still appears to have something very troublesome, even thought there is no SLS.