WOW! I cannot believe that the Hartz company would even put something like this on the market!! I Have given this to my poor chihuahua for several months now. And he has been so severely sick! His back legs were immobile, Vomiting, Diarrhea and not to mention the horrible cries me makes often!! And this is a month after his last dose!!! I couldn’t figure out what has been wrong with Plum. I had been giving him the Flea and tick liquid that you run down his back once a month. As well as the mite ear drops!!! Plum now has open sores on the tips of his ears, and a couple on his underbelly!! I am thankful that my precious dog has not died from this but I am so very sorry for the people who have lost their precious pet because of some sick company trying to make a couple bucks!!!!!!!! DO NOT CONTINUE USING ANY OF THEIR PRODUCTS!! I have to now make my dog an appointment for the vets and hope there is no serious damage to his liver or kidneys or who knows what!!!!! I AM SO SORRY THAT I HAD EVER GIVEN HIS ANY OF THEIR PRODUCTS!! HE ALMOST DIED!!!!!