Every time I bite my lip it was guaranteed to become a canker sore. I tried everything to prevent them but nothing worked. My life changed when I read that SLS (sodium lauryl sulfate), the ingredient used in toothpaste to make it foamy, aggregates canker sores. I got a new toothpaste and lo and behold ever since I haven’t had a single sore (except for the week I left my toothpaste at home while on vacation). I didn’t think I would ever see the day where I didn’t have to worry about getting a canker sore but my life has been changed ever since.