Deflea rtu cat shampoo 8 oz. attacks the physical structure of the flea or pest by dissolving the waxy protective coating.,The other active ingredient(primarily a laxative in laymens terms) is then able to penetrate the f.,Apply deflea shampoo onto coat of pet.,Work shampoo into pets coat until a lather forms.,Treat the entire pet including hard to reach areas such as between paws.,Rinse animal & dry thoroughly.Undecylenic Acid