I think fleas are developing immunities to all the other ones and the chemical make up of activyl is different enough that they havent had the time to become immune yet

I noticed less scratching within hours and it kept on working now i have happy itch flea free dogsif you are looking for something that works and have tried just about everything else

Give this a try i think you will be happy and flea free when you do did the job my papillon is allergic to flea bites so the oral medications do not protect him from flea bites or me from costly get bills if he is bitten

Keep flea off my dog so he is health and not scratching first time i have used the product and seems to be doing good