I used the flea and tick product on my 16 month old dog and i almost killed her with this product. I applied it on her and 2 days later i was walking her and she colapsed on me and couldn’t stand. We took her to the vet and when the vet seen the Hartz package in my hand they said………I HOPE YOU DIDN’T USE THAT ON YOUR DOG. They did bloodwork on my dog and it came back that she had Liver Failure. The vet said it was fron a toxic ingredient in the Hartz product. 400.00 it cost for meds, bloodwork and follow up bloodwork. So far she is fine but the vet wants to see her in 3 months for a final follow up. I called the Hartz company to complain and i was told they never had any complaints about thier product. When i told them about this site they said they will not listen to anything i tell them about the internet that anyone could make up stories.