I have never used it. I don't have any sensitive dogs, but I do have a cat who is incredibly sensitive to gluten/artificial colors and flavors. Reading the labels on the plaque sprays at the pet store led me to believe that it was not a good idea. There were ingredients in there that would probably cause her to react. Also, a friend saw someone in the waiting room of the vet with a dog whose mouth was a mess. He was allergic to the plaque spray. If you are unsure, don't risk it.