Bests & Worsts Reviews from Amazon

I have been a cat fancier for almost 40 years so I do have some experience on this subject. I currently care for 4 indoor cats that have been inside their entire lives. Two males weighing about 14lbs and two females weighing 10 and 12 lbs. They just turned 5 years old, are litter mates and are spayed and neutered. I have used original Advantage on them for years with fine results. However, I CANNOT say the same for Advantage II. It appears Bayer's patent expired on original Advantage so they concocted the new and "improved" Advantage II. Well, the hair on the back of my cats' necks falls out where the Advantage II makes contact with their skin about 2 days after I apply it. And, they keep scratching as if they have fleas. This NEVER happened with original Advantage. This occurred both times I used Advantage II to all 4 cats so I know the first application was not a fluke. I am not happy with the new Advantage II and am looking for an alternative. It obviously is causing harm to my cats and is not as effective. This has been my experience. Your mileage may vary.