I bought Colgate smart white with foaming action for sensitive teeth about a month ago because the store was out of normal Colgate Sensitive toothpaste that I have used for years. My mouth has burning ever since but I only put recently put all together that it was this toothpaste. My gums around my teeth burnt. I even had bad pain in my teeth. The tip of my tongue and my lip has got burning sensation. The pain and burning sensation was gradual over time. I have used it for over 5 weeks. I quit using this product 4 days around still no improvement. I have tried everything for relief and I get only partial relief. Colgate smart white for sensitive teeth should come with a warning to consumers. This product contains harmful chemicals that actually effects bad to your mouth.