Catnip
(Nepeta cataria)
Catnip is of Asiatic origin and contains a chemical called nepetalactone, which is present in its leaves and stems. This chemical has a very powerful effect on some cats.
When a cat (normally over three months old) approaches the catnip plant and sniffs, it starts to lick, bite, chew, and repeatedly rub against it with its cheek and chin, shake its head, purr loudly, growl, miaow, roll over and over. Catnip seems to produce some sort of ecstasy drug trip, although unlike human drugs, after the cat's experience it soon goes back to normal with no ill-effects.
Catnip is not the only plant to produce magnetic effects on cats. Valerian (Valeriana officinalis ) and Actinidia polygama also produce strong cat-appeal.