Frontline is a very good flea medication for dogs and cats. In fact, I would say it might be the best product on the market for fighting fleas.
There may be newer medicines available, but Frontline is tried and true and has been around for a long time. It is extremely well tolerated by most pets and has few side effects which is one of the reasons why it is recommended so widely by veterinarians and other professionals.
It takes about a day for Frontline to become fully effective after you give your dog its first application, but after that it kills fleas on contact within a matter of hours and will kill the entire flea infestation including juveniles within a matter of a few weeks or months.
If you’re looking for a good flea medication for your pet, I would say that Frontline or Advantage are probably the two best available.