I tried Hartz flea medicine on my 12 year old cat I have always given her Advantage but was at Walmart and picked up the Hartz. A few days later she started acting weird, not eating or drinking and acting like she couldn’t move. She also stayed under my bed and was just not acting like herself. I thought at first she got bumped by one of my kids or was just sick. I took her to the vet and they said maybe a bladder infection and maybe she got bumped but she didn’t have a fever and other than the symptoms I described looked okay. Not being 100% with the diagnosis I started looking on the internet for other possibities. I remembered giving her the flea medince a couple days before and also my husband thought he asked the Vet to put some Advantage on her. I started thinking maybe she was having a reaction from a double dose of medicine. Thats when I found your site. Thank goodness the Vet didn’t apply the Advantage because they didn’t have it marked so she wasn’t double treated. But now that I have read the stories on your site I am convinced that it is the Hartz flea medicine. Thank goodness she hasn’t had a deadly reaction but she must be having a mild reaction. She’s better today and hopefully the stuff will get out of her system soon so she can get back to normal we can only pray it hasn’t caused permanent damage. It seems like there is something more we can do this product is criminal. THese pets are our family.