Frontline Plus Flea & Tick Drops for DogsDetails Frontline is the #1 name in flea and tick prevention for dogs and cats! See size chart. Can be used on puppies as young as eight weeks old, weighing 5 pounds or more. Fast acting, waterproof, and easy one spot topical. Formulated with fipronil and (S) methoprene to kill fleas, flea eggs, flea larvae, chewing lice, and ticks which can transmit Lyme disease. Remains effective even after bathing, water immersion, or exposure to sunlight. Each