Hi Farruska,
Catnip is the common name for an herbal plant of the mint family that grows wild here in the US. It got it's name because cats seem to go crazy over it, somehow it has a smell and taste that they just can't get enough of. My Bo will eat the dried leaves. She also literally chews to pieces anything that has catnip rubbed on it (such as her furry mice).
Not all cats like it, however. Our first cat, an orange tabby named Valentine, couldn't have cared less about the stuff. He was a bit unusual in other ways, too....didn't care for any kind of seafood, just preferred beef and roast fowl.
You might try to do an Internet search using the term "catnip" just to see what comes up.