Since its introduction by Bayer in April 1996, Advantage has become known as "the flea specialist" and is the fastest flea control in a tube. Advantage kills 98 - 100 percent of adult fleas within 12 hours of application, and reinfesting fleas are killed within two hours. It kills fleas before they have a chance to lay eggs -- therefore breaking the flea life cycle.Advantage is applied to the back of the neck on cats and between the shoulder blades on dogs. It spreads naturally on the skin surface at the hair root level, aided by body movement to provide whole body coverage. Advantage a is water-resistant flea medication, so it continues to kill fleas even after a shampooing, swimming, rain or exposure to sunlight.