Lisa writes: Or, "Weirdnesses: Continued." Lisa is strongly of the opinion that sodium lauryl sulfate causes, or antagonizes, canker sores. (You never want to antagonize a canker sore. They're cranky.) It does not, as is often hysterically reported, cause cancer , and is just fine in shampoo and dish detergent, etc. It's just a foaming agent. It makes bubbles and breaks up oils. This is great in your hair and on your dishes, but it's a problem in your mouth. Ever touched a fish? You know how they have that thin slime layer on their scales? And if you touch them with a dry finger, they'll get a sore there because you broke the slime layer? The mucus membrane in your mouth has the same thing, and if you are genetically predisposed to canker sores, using SLS breaks up the protective slime layer (maybe I should find a better word for it?) and lets those bad germs get in. Which is why I am a fan of: - Rembrant Sensitive or Rembrant Canker Sore toothpaste - Sensod...