I saw a post about Hartz on Facebook about the harsh effects it has on pets and it reminded me of what happened to my three yorkie about 4 years ago when I used the hartz flea and tick ultra guard product on them with in minutes all three of my dogs started going nuts! They started inching like crazy and rubbing their backs on the ground, when I looked at where I put the drops there was a red patch on each dog. I gave them each a bath and brought them to their vet and they said that my dogs had an allergic reaction to the drops and was left with mild chemical burns. The vet gave me some kind of cream to put on the burns to help them heal. After that I never bought those flea drops again. I buy flea and tick drops from my local vet and have never had any reaction. Yes the drops from the vets office are a bit more pricy but at least I can sleep at night knowing that my dogs won’t potentially die from the product. Don’t buy product just because they are cheap… they are probably cheap for a reason!