The only "horror" stories I have heard about with Frontline or Advantage is if people give the dog formula by mistake or try to use the dog formula on their cats, in smaller quantities, to save money, or apply it to a young kitten, below their recommended weight and age.

If you study on this stuff, the dog formula contains a substance that is highly toxic to cats in many cases. Wish I could tell you exactly the name right this second, but I can't remember anything except it starts with a "P". Anyway, the cat formula is different, and pound for pound, is far more expensive than the dog formula.

We have never had a problem using Frontline Plus on our cats.