In the summer of 2019 we were unable to buy our normal flea and tick topical treatment so we went with hartz. Within a week, all four of my cats were foaming at the mouth, had raspy breathing, and lethargic. As each got sick we took them to the vet. It was a some sort of severe respiratory infection and they were quickly dying. Luckily three of them took the concoction of meds and are well. But my oldest cat didn’t make it. We were devastated. The only new thing my cats were exposed to new was hartz flea topical treatment! My vet warned me to never buy it again!