Why Catnip works for Cats: Catnip is a herb that emits a chemical that makes your cat or kitten lick, purr or roll head over tail. Catnip seems to work differently depending on the cat but seems to make them playful. This is useful for cats that claw furniture. You can purchase catnip toys or get the oil to rub on scratching posts. For cats that don't seem to react to catnip, try the Honeysuckle Chip.