Oral flea treatments such as tablets and chews are great for treat-loving dogs – as long as you can convince them that a flea chew is something tasty, of course. These treatments are absorbed into the bloodstream, meaning a flea is only killed when it bites your dog and ingests the active ingredient. You only need to administer an oral flea treatment every three to four months, and it often contains a deworming treatment, too. Flea collars contain an insecticide that kills or repels adult fleas via a constant slow-release of chemicals. These collars start working within 24 hours of being fitted around your dog’s neck, usually offer full protection for a few months, and are most effective when they’re prescription strength. It’s important to note that a flea collar should only be used in addition to your dog’s normal collar, as they aren’t designed to hold the weight of a dog lead.