Catnip, Nepeta cataria, is a member of the mint family, imported probably from Europe, though originally native to the Middle East, that went wild and now flourishes everywhere. It grows about 2' tall. The leaves are downy above and below, a little larger than peppermint leaves, and was said to be a good tea to drink to bring down fevers, as well as pleasant-tasting.

Catnip, a member of the mint family, is harmless for felines. Although many cats will eat it, scientists say they're reacting to the smell rather than the taste. Felines bite, chew, rub against, and roll in catnip to release the volatile oil trapped in the leaves.

About 80% of adult cats -- including lions, pumas, and leopards! -- react to this irresistible, intoxicating, analgesic soporific. The tendency to like or ignore catnip is inherited, and it's true that some cats are immune to its influence.

Here's some links to more information about Catnip.

http://www.holoweb.com/cannon/catnip.htm