If your pet is infested with fleas and you take it to the vet, the first thing they will probably do is administer flea medication.
The two most popular brands of flea medication in veterinary and offices are Frontline and Advantage. Both of them are very effective and both of them will kill almost 100% of adult fleas within 12 hours of the first application. Each application is effective for up to one month.
The vet may also give your dog a bath using a flea control shampoo, which will also quickly kill and remove any adult fleas, flea larva, or eggs on your pets skin or attached to its hair.