In 1999, my cat had seizures immediately after giving him a liquid Hartz flea treatment drops in the tube. He didn’t die, but it took 6 months for the seizures to go away. It was much cheaper at Wal Mart than Frontline at the vet. I called Hartz to let them know. Of course, they denied it was their product. That was my first and last time with purchasing Hartz. My cat suffered every day for 6 months. Luckily, he survived 8 more years to the age of 10.