I received a sample and was sold. I am on my second bottle in probably 6 months. I only have to use a tiny amount every day or two and I haven't had a canker sore/mouth ulcer since I began using it. Normally I get them 4-5 times a year. It is a great product and I am amazed at how long a bottle can last. Update: I hadn't been for a teeth cleaning in about 3-4 years and my hygienist said my gums were in amazing shape. I swear this is the reason for that. I am buying more and some of the toothpaste as well.