Frontline Plus is made of two major ingredients, such as 9.8% fipronil and 8.8% S-methoprene while the inert ingredients remain for the rest. The best thing about this treatment is that it starts working very quickly and just after applying the Treatment and continues to work for as long as a month. Just within 24 hours of applying the Treatment, the dogs become completely free of fleas and ticks. Once you apply this Treatment, there is only a 24 hour period of wait after which you can take your dog for a swim. Fleas and ticks often develop resistance to Treatments but with Frontline Plus, such cases are really rare and insignificant. The dogs and cats after applying the Treatment can only experience a little skin irritation which will eventually subside just after 24 hours. As far as resistance is considered you need to be observant about the situation and based upon your veterinarian’s advice should apply the Treatment.