Frontline Spot On Dog Flea & Tick Preventative Treatment Large Dog. Frontline Spot On Dog Flea & Tick Preventative Treatment kills fleas and ticks and controls biting lice on dogs and is a quick and easy way to treat your dog. Frontline Spot On is easily applied with the pipette directly to the skin between the dogs shoulder blades and kills fleas within 24 hours and ticks within 48 hours. Please ensure instructions are read and followed before application. Suitable for medium dogs 20-40kg. Contains 1 pipettes.