Protect your dog with the UK's number 1 flea and tick protection. Suitable for medium-sized dogs over 8 weeks old. Frontline Spot On is a fast-acting and long-lasting solution to protect your dog from ticks and fleas, and the diseases they can carry. How it works Frontline is absorbed into the skin and distributed with the natural oils all over your pet's body. Rather than entering your dog's bloodstream, Frontline kills parasites as they make contact with the skin. Using Frontline Spot On every month helps keep your dog safe from ticks and fleas, so you can keep on sharing quality time together without any worries.