Beaphar FIPROtec COMBO Spot On for Large Dogs contains fipronil and the insect growth regulator S-methoprene. It not only kills adult fleas, ticks and biting lice, but also interrupts the flea life cycle, preventing any exposed eggs and/or larvae from developing in your home for up to eight weeks. FIPROtec COMBO for Large Dogs kills adult fleas for up to eight weeks and ticks for up to four weeks. Suitable for dogs over 8 weeks of age and weighing 20-40kg. Suitable for use on pregnant and lactating bitches. Dogs who spend a lot of time outside are especially at risk from fleas and ticks. It is important to establish a regular flea control routine for dogs and the household.