There are many medications on the market for dog fleas and choosing the best dog flea medication is difficult. They all work a little differently, by different mechanisms and many have cross coverage (meaning some will not only treat dog fleas but also kill ticks, prevent heartworm disease, or treat common intestinal parasites).
Choosing the best dog flea product for your dog will depend a lot on what he needs, what cross coverage you may want. Another factor that may affect your choice of dog flea control products is the formulation that you prefer for your dog. There are different formulations of either liquid or pill and some dog owners prefer one over the other.
Since the question was just about "what is the best dog flea medication", there are three drugs that are commonly used to treat just dog fleas. They include: Program®, Capstar®, and Advantage®. Program® is a good preventative as it prevents dog flea eggs from developing. Capstar® kills adult dog fleas but doesn't work to prevent eggs from hatching and is often used with Program®. Advantage® prevents and kills fleas.
Other products work to treat dog fleas and ticks such as K9Advantix®, Promeris® Duo, Frontline Top Spot®, and Frontline Plus® K9Advantix® - prevents and kills dog fleas, ticks and mosquitoes. Other medications also prevent heartworm disease in addition to the dog fleas such as Revolution® and Sentinel®.
Discuss dog flea control with your veterinarian to determine the best dog flea medication for your dog. For more information about choosing the right dog flea products, click here