I have used Revolution on cats AND dogs since it came on the market. The company provided it for free to animal shelters for a few years, and it was the best product I had ever tried- the rescue would have so many animals brought in who were so infested they were dehydrated and close to death, and the Revolution took care of every single flea in 24 hours or less. We had no problems after that with fleas anywhere- on the critters or in the environment. It is supposed to work on ear mites as well, but from experience, some of the critters had mites so bad, we felt the best solution was to clean the ears and treat the mites as well as using the revolution on them, so I can't verify whether it killed serious ear mite problems on its own or not, but I CAN say they never got reinfected with mites once we cleaned and treated them. Maybe its prevention, maybe it is a cure- can't say for sure.