It gets its name from the unusual behaviour of [domestic cat]?s when they smell the bruised leaves or stems: purring, salivation etc. It is not known why cats respond in this way to catnip, but studies have identified the component chemical in catnip as a lactone? compound called nepetalactone.
The root of a completely unrelated plant, valerian, has a similar effect on cats, but it is not known what the active constituent of valerian may be.
Classification: Catnip is a member of the mint family, Lamiaceae.