We use Frontline Plus for dogs, monthly. So far, it works. Puppy came with fleas, two months ago. Put the Frontline on, and within a few hours, they were gone and no more itching. That is the good news. The bad news is that it is VERY PRICEY!!! It was cheapest at our local Target. It came in a 3 dose package, so it runs about $20 per month, but worth every penny, if we have no fleas on puppy or in house/yard. Our winter was so mild, it did not kill any bugs or pests, so we will continue this treatment, as long as it works. Good luck!!!