True story: 12ish years ago, I used Hartz flea drops, for cats, on my cat Isis. I followed the instructions on the box, which told me to put the stuff all the way down her spine from the base of her neck to the base of her tail. Of course, being a cat, when there was some foreign oily stuff in her fur, she groomed herself to GETITOFFGETITOFF. Next thing I know, she’s going into convulsions. I had to take her to the emergency vet and have her stomach pumped because she ingested poison! $300! Half of which I had to borrow from my brother, because who the heck has 300 extra dollars laying around? Since then I have never ever used any Hartz products and warn all my friends against using them too.