Control of parasites in dogs is a key responsibility for veterinary professionals. The area is complicated because dogs need tailored therapy, there is an overwhelmingly large choice of parasiticide products on the market and very intense promotional activity by drug companies. The aim of this module is to help veterinary professionals use parasiticides rationally. It covers the five main parasites that affect dogs in the UK and the parasiticide drugs used to treat them and outlines the different approaches to parasite control.