I am a retired vet tech. Most flea collars only keep the fleas away form the collar area; the rest of the body is free game for the fleas! There have been alot of newer and better flea products. Alot of them have been mentioned already. One hint tho, if you dog is a short haired dog the Advantage, Frontline etc. just gets rubbed or shaken off. There is a new product that is in pill form called Comfortis. Works great for me. I only use it twice a year just for insurance. If fleas are bad in your area remember to spray your yard.