Seresto^®kills fleas and ticks. Seresto^® was designed with specific ingredients at doses that are active against fleas and ticks. ... Imidacloprid has been used in products for years to control flea infestations. Flumethrin effectively kills and repels ticks.

Do Seresto collars really work?

As well as preventing fleas, Seresto is an effective tick treatment. If your dog has a tick attached to it before you put the collar on, it can take up to 48 hours for these to be killed so we would generally recommend removing any ticks that are already attached.

How long does it take for Seresto collars to start working?

Seresto kills existing fleas on dogs within 24 hours after application. Once collar has been on your dog for 24 hours, re-infesting fleas are killed within two hours. Infestation prevention with new ticks starts within 48 hours after Seresto collar application.