So, what is catnip anyway?

Catnip is one of the approximate 250 species in the mint family and has a leafy green appearance. Nepetalactone, the essential oil in catnip, can turn even the laziest couch potato into a crazy furball—if said furball happens to have inherited the sensitivity to its effects. The trait doesn't emerge until a cat is between three and six months old; until then, a kitten will not have a response. Catnip sensitivity is hereditary—an estimated 50 percent of cats have no reaction.

Smelling vs. Eating

The most intense catnip experience starts with the nose—one whiff of the stuff and your cat promptly goes nuts. Researchers suspect that catnip targets feline "happy" receptors in the brain. When eaten, however, catnip tends to have the opposite effect and your cat mellows 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.

Usually these sessions last about 10 minutes, after which your cat loses interest. It may take as long as two hours for him to "reset" and become susceptible to catnip again. Be mindful of overindulgence though—cats are unlikely to overdose on catnip, but they can get sick if they eat too much. Trust your kitty to know when they've had enough.