Years ago I used the Hartz liquid drops on my cat. The next day I noticed she was not eating and was lethargic. I wiped her neck and luckily she was back to normal in a day or 2. I Google Hartz and realized what it was and how lucky she was compared to the hundreds of horror stories I’ve read. Fast forward to today. I take care of a stray kitten we found in my yard a few years ago. He didn’t come home for dinner last night and when he came home today, he had a Hartz collar on him and he was acting weird and not eating. Someone in my neighborhood put the poisonous collar on him and I am so pissed. Who would put a collar on someone else’s cat who already has a seresto collar on?! I immediately took it off and he’s started acting normal. Again, he was lucky. I really don’t understand how Hartz is still in business after years and years and hundreds if not thousands of animals have been affected.