Adams Fortress Spot On Flea and Tick Drops for Medium Dogs and Puppies Weighing 23 to 44-Pound Kills fleas and all stages of brown dog ticks, American dog ticks, lone star ticks, deer ticks (which may carry Lyme disease) and chewing lice When used monthly, Fortress Spot On for Dos completely controls flea, tick and chewing lice infestations Remains effective even after bathing, water immersion, or exposure to sunlight For dogs 8 weeks or older; 3 Month Supply