"I was skeptical, but tried this stuff anyway. The other product did not kill all the fleas! So I tried Frontline Plus, hoping to relieve at least some of the scratching my cats were suffering from. I could see an almost immediate effect, but after 5-6 days, there was a definite result. Very little, if any scratching! (How much is just a normal itch?) As far as I am concerned, Frontline Plus is for me! (Sounds like a TV ad? - Yes but it's the truth!)"