I purchased this product yesterday morning, and applied it to my cat at 12:30 pm. By 5:00 pm, he had been rushed to the vet hospital from full body tremors. He was instantly taken in and given a shot to calm him, and a shot of muscle relaxer. I was given a bottle of muscle relaxers to bring home to give to him every 6 hours as needed for tremors, as they can cause fever and dehydration. He has been sleeping since I brought him home last night due to the muscle relaxers, and is having a hard time eating and drinking. The vet said he will be fine with no long term effects. I feel like I am one of the lucky one’s after reading other people’s stories about Hartz and their pets dying. I am outraged that this product is on the shelves! The vet even told me NOT to use Hartz…it’s pretty bad when a vet even says not to use it.