Frontline you need 48 hours before or after a bath. It goes into their oil glands and bathing strips those clean...
When you give your dog a bath fleas don't usually drown because thye have this nice like waxy coating overy their bodies and can survive...dish soap or any shampoo applied directly breaks down that waxy coating and then they DO drown...bad news? It dries out you dogs coat SOOO bad and don't get it in their eyes!!!
Capster kills the fleas with mins to hours, some groomers use it to treat dogs, but it does not last.
Comfortis is the new pill on the market, it is oral and therefore bathing is not an issue.
Fleas are usually brought into a home by the HUMAN not the dog. Easiet way for your dog to get fleas is to be in contact with someone else who's dog/cat does have fleas, you catch one of those flea eggs (which are microscopic) and come home and play with your dog and the egg falls off...well those little eggs can live in your home wiht the right conditions up to 6 months with no food source...
Vacuuming your home will help keeop down an infestation, change the bad afterwards
I prefer Advantage, but there are a huge range of products available. just remeber that flea baths and dish soap baths only work for a few days, then they hatch...