RE: Carbamide peroxide I am not a dentist, but this is what I surmise: As you all know, there are people who use hydrogen peroxide or hydrogen peroxide products to clean and whiten teeth. It acts as an oxidizing and bleaching agent. Solutions of hydrogen peroxide gradually deteriorate and can be stabilzed by the addition of organic materials, carbamide in this case. My conclusion is that as long as the mother spits the stuff out after brushing and does not swallow it (although I am not sure who would want to do that) all is OK. Even if she swallowed any of the stuff, the GIT would "eat" it right up.