Catnip is a plant that is a member of the mint family, and its scientific name is Nepeta cataria. It contains an essential oil called nepetalactone, which is the active ingredient that triggers a response in some cats. Catnip is not harmful to cats, and it is safe for them to ingest. However, most cats wont react to catnip until they are 6 months to 1 year of age. Some cats can be exceptions to this rule, as they will slowly increase their sensitivity over the years. The most intense catnip experience starts with the nose, and one whiff of the stuff can make a cat go crazy. Researchers suspect that the herb targets feline "happy" receptors in the brain. When eaten, however, it tends to have the opposite effect and can make a cat mellow out. Most cats react to catnip by rolling, flipping, rubbing, and eventually zoning out. They may meow or growl at the same time. Other cats become hyperactive or downright aggressive, especially if you approach them. Common behaviors cats display when they sense the bruised leaves or stems of catnip are rubbing on the plant, rolling on the ground, pawing at it, and licking it. Usually, these sessions last about 10 minutes, after which your cat loses interest. It may take as long as two hours for a cat to "reset" and become susceptible to it again.