I used the Hartz flea and tick medication on my two cats this past Sat. and by 10:00 Sun. night one was drooling and having seizure like convulsions. His eyes were glazed over and he acted like he could not wake up. I rushed them both to the emergency vet. One is still not out of the woods yet, but the vet said he has seen this before and is pretty sure he will be ok. He said if I had not been home he most likely would have died! He said this product is extremely toxic to cats and has killed many and told me there is a class action law suit. I emailed Hartz and planetfeedback.com. How can they let this stuff stay on the shelves? How?! I also emailed the Bi-Lo store I purchased it at and begged them to take it off their shelves.