My cat was a healthy active cat until I used Hartz flea and tick drops on her. She started to have seizers and other problems I took her to the vet and the drops were concluded as the cause of her illnesses. She took medication to help control the seizers but as of Easter Sunday April 16, 2006 she had a large stroke and did not recover. I had to have her put to rest April 19, 2006. I know Hartz robbed me and my cat of many happy years together.