While our cats are often models of grace and composure, some of them can achieve altered states of drooling relaxation or fits of frantic energy just by getting a whiff of a little bit of catnip. But what exactly is catnip, why does it have such a strong effect on some cats and not others, and is it in any way harmful to our cats? In this podcast, Dr. Gayle Sternefeld, senior associate veterinarian at the Cat Hospital at Towson in Baltimore, talks about catnip.