Susan is my 2 1/2 month old kitten who has recently had a flea issue, I went to my local CVS and picked up this Hartz drops that you put on the back of their neck so that they cannot lick it. I gave her this medication at about, 11:30pm. At 8:30 in the morning I awoke to Susan having a seizure ontop of me. I rushed her to the vet and she has now been there for 24 hours and I am able to pick her up in the morning. To think that I almost killed my own cat makes me sick, even more so that others will go through this traumatic experience.