Catnip (the stuff that makes cats go mad) is a type of a certain herb, can anyone tell me what it is?
Thanks in advance,
Ben.
The Straight Dope Column on this subject says in part:
This isn’t related to a Staff Report, so I’m moving it to General Questions, even though it’s answered by Cecil. Ben, you might please want to check the descriptions of the forums before posting?
Cats can display catnip-like behavior in reaction to other minty substances. I had one cat who’d go wild whenever I slathered on Ben-Gay, trying frantically to burrow through my clothes (or covers if I were in bed) to get at and lick the slathered anatomy. I’m convinced it was the minty aroma that triggered the drug frenzy.
The plant looks very much like any other mint plant. Around here they usually sell it with the other herbs in the spring at places like Lowes and Home Depot.
In Ben Hicks’s duplicate thread, What is Catnip?, catnip is correctly identified as nepeta cataria. So the strict answer to this question is:
“Catnip” is made from nepeta cataria, commonly called catnip.
Warning if you buy catnip plants and put them in your garden:
Catnip is a mint. Like all mints, it is extremely hardy, proliferate, and aggressive. Once it’s in your garden, it is very hard to get it out again. 
This is a good thing if you don’t like to spend a lot of effort on the garden, but just be warned in case you ever decide to change your garden around – you’ll be weeding mint for a few years afterwards!
Plus, of course, it may attract the local felines, which may or may not be desirable, depending on how much you like cats.