Frontline gets in the dog or cats blood and when the fleas bite the animal they die. Doesn't take long to get rid of all the fleas and ticks . It works for me. I have 2 dogs and 5 cat outside and a very cute chihuahua and schnowzer(I know I mispelled them both) mix 4 mo. old in the house.
It's a monthly application ,one pill a month, cost depends on size of animal. Probably no better than the $14 someoneelse mentioned. but its worth every penny. Cost way more than that with all the grandulars and sprays. and still have fleas.