Within a few hours of putting this on my cat (EXACTLY as instructed by the box) she began to have neurological symptoms, such as twitching. She was literally drugged. She was sluggish, twitchy and drooling. We tried taking a wet towel and rubbing it off, but the next morning, it was still all over her neck. Her pupils were dilated and she was twitching even worse than the night before. I called a vet that told me to wash her down IMMEDIATELY with Dawn soap. Since she was already so scared, she was almost impossible to bathe. We brought her to the vet where they had to sedate her, bathe her again, and give her fluids to try and flush this poison out of her system. The vet says they see HUNDREDS of cases of Hartz products poisoning pets. I don’t know how they can legally sell something that kills your pets. If you love your pets, please do not buy this product. If I had done even a small internet search of this brand I never would have bought this. Every single review I have seen has been negative. I just hope I can save someone else from a costly vet bill, or even the death of their pet. Fortunately she’s going to be OK, but I will do everything I can to make sure people know about this horrible product. Shame on Hartz, and shame on WalMart for carrying it.