We have four dogs all on flea and heart worm medicine. It is costly. BUT now they have come out with a combination of both flea and heart worm pill called "Triflexis" it is a lettle cheaper than giving separate pills. We give it once a month according to the weight of the dog. It doesn't rid the dog of fleas but as soon as a flea bites them it dies. so as a result all fleas dissapear. It also kills ticks that get on the dogs.