K9 Advantix II Dog Flea & Tick Drops is a topical prevention and tick, flea, and mosquito treatment for monthly use on dogs and puppies 7 weeks of age and older. 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 for up to four weeks. Effective flea treatment kills 98-100% of the fleas on dogs within 12 hours and continues to prevent infestations for at least four weeks and kills fleas before they lay eggs. Larval flea stages in the dog's surroundings are killed following contact with a K9 Advantix II treated dog and repels and kills mosquitoes for up to four weeks also remains effective after bathing and swimming. Convenient, easy to apply K9 Advantix II For Dogs kills fleas which may cause flea allergy dermatitis (FAD). Advantix II For Dogs kills 98-100% of the existing fleas on dogs within 12 hours. Re-infesting fleas are killed within 2 hours with protection against further flea infestation lasting at least four (4) weeks. Pre-existing pupae in the environment may continue to emerge for six (6) weeks or longer depending upon the climatic conditions. K9 Advantix II Dog Flea & Tick Drops remains an efficacious tick and flea treatment following a shampoo, swimming, or after exposure to rain or sunlight. Monthly tick & flea treatment is required for optimal control and prevention of fleas and ticks. Does not expire if package remains unopened and is stored properly according to instructions. Please note that the product information displayed is provided by manufacturers, suppliers and other third parties and is not independently verified by Petco.