Read the Entire Label Before Each Use For the Prevention and Treatment of Ticks, Fleas, Mosquitoes, Biting Flies and Lice on Dogs Repels and kills ticks including Deer ticks (vector of Lyme disease), American dog ticks (vector of Rocky Mountain spotted fever), Brown dog ticks (vector of Ehrlichiosis), and Lone Star ticks (vector of Ehrlichiosis) for up to four weeks. Repels and kills all life stages of fleas. Prevents fleas on treated dogs from infesting your home. Kills fleas on dogs within 12 hours and continues to prevent infestations for a month. Prevents development of fleas, flea eggs, pupae and larvae for a month. Larval flea stages in the dog's surroundings are killed following contact with a K9 Advantix II treated dog. Repels and kills mosquitoes for up to four weeks. Repels and prevents blood-feeding by biting flies. Kills chewing lice.