smoking it? You chew it, you can smoke methcathinone (I think) if that is what you were thinking? I believe that Khat contains both cathine or cathinone.
Its used in Africa by fighters like meth was by the US Army 50 years ago... Chew enough of it and they can fight for days after being shot several times. But its spelled Khat and pronounced "cot" Nasty stuff...