I gave Hartz flea drops to my cat last spring. He became lethargic, went into hiding in the closet, had difficulties breathing, was non responsive. He would not eat or drink. I googled “Hartz” and the FIRST page that popped up was this one, about the Hartz victims. I freaked out, I had no idea. We thoroughly washed the area where I had administered the drops and he slowly started coming back. After a long night of me holding his paw and monitoring him constantly he came around. I took him to the vet, switched to Revolution, and am plenty happy to pay the extra money and have a healthy happy cat. HARTZ KILLS.