Frontline Plus is a topical means of protecting your dog from fleas and ticks -- you apply a liquid form of the insecticides fipronil and S-methoprene between your pet's shoulders, and it absorbs into the body through the skin. Because Frontline Plus is topical, you have to wait a couple days before you can bathe your dog, or the prevention is less effective.
Wait 48 Hours Before Bathing
Once Frontline Plus is applied, you will need to wait 48 hours before bathing your pet. This gives the product enough time to be absorbed by the dog's skin. If you do bath your dog before 48 hours elapses, you risk the medication not being as strong. Keep your dog out of the rain and away from his favorite swimming hole during those 48 hours.
Bathe With a Dog-Friendly Shampoo
It's important that you always use a gentle dog shampoo. Never use a flea wash in combination with Frontline Plus. Never use human shampoo, as the pH of human shampoo is different from what's necessary for your dog's coat. A gentle dog shampoo won't strip your pet's coat of the oils that keep it healthy. Seek veterinary advice if your dog has a skin condition that warrants the use of special shampoos.
Resume Regular Bathing After the First 48 Hours
After the 48 hour time frame, dogs can be bathed and go swimming. The medication is water-fast after 48 hours. You do not need to worry about baths or other water activities disrupting the medication. If your dog rolls in something stinky after those first 48 hours, feel free to scrub away the stink.
Bathe Before Application
Because dogs can't be bathed for 48 hours once Frontline Plus is applied, it's a good idea to bathe your dog before applying the medication. However, your dog must be completely dry before applying a treatment. Wash your dog early in the morning and apply Frontline Plus at night, or wash your pet the day before his application is due.