Bests & Worsts Reviews from Amazon

My cat just died a really bad, painful death, and I feel like this was at least partially responsible. I'm writing this to hopefully help someone else. My cat was pretty old and I would say his health was fair (not good, not horrible), I used about one third of a tube of this on him (I split one tube among 3 cats). I thought this was regular Advantage which I have used in the same way for years and have never had a problem with. My cat started laying around, not eating, not drinking, not going to the litter box. Started having trouble breathing and then died with convulsions. Through this process, I thought maybe this was just a very old cat getting sick and he would come out of it, but one of my other cats started laying around too (thankfully, he seems to have come out of it). The scary thing is that, since this was a VERY arthritic cat, I'm 99% sure he didn't lick any of this off of him, so it did this much damage just being on his skin. I blame myself since I should have checked out exactly what I was using (the regular v.s the "2"), but I feel like I should warn people that this is strong stuff and I would not use it on a young cat, old cat, sick cat, or any cat that I loved dearly--it's not worth the risk. Regular advantage works well. Use that instead--and be sure to check the label because the tubes look pretty much the same (and yes this was purchased from my vet).