Seresto is a flea and tick collar for large dogs over 8kg, delivering continuous protection for up to 8 months from a single application. Made by Elanco, it uses a controlled-release mechanism to distribute active ingredients across the coat rather than relying solely on direct skin contact.

The collar contains two active ingredients — imidacloprid (100mg/g) and flumethrin (45mg/g) — which work together to treat and prevent flea infestations, control paralysis tick, kill larval flea stages, and manage flea allergy dermatitis. The design is odourless, adjustable to fit most large breeds, and water-resistant, so protection holds through swimming, rain and bathing.

The appeal is straightforward: eight months of coverage without monthly applications, topicals or tablets. The water-resistant construction means no need to remove the collar before wet-weather walks or swims, which owners of active large breeds tend to find worth the investment.