Who decides that certain naturally occuring herbs are illegal 2 smoke?

like didnt ancient man ever light up a spliff when he invented matches and cigarette papers?

Ehrrmm.. I nowadays smoke things that come off plants, but I wouldn't call them entirely natural, considering they've been 'bred' for lack of a better word, to have a more severe impact. In my native country, some popel wonder if a spliff with a THC content of 24 percent could still be classified as 'soft drugs'. But, to answer your question: the people most firmly against it, are the ones who smoked it themselves when they were young and in college - and appaled at their own memories. It works like that, really it does - it's why you'll find extremist conservatives have a communist past, and why less and less money is going to education - because older people seem to know it's all been a waste of time. In short: pedantic old people decide. And unfortunately, while they need hearing aids, we listen. Be an IMBY eh ;o)

naturally occuring herbs are illegal because the ignorant can still vote.
Well I'm guessing government bodies decide. But I also question why some things are illegal and others not - like alcohol.

Mind you alcohol used to be illegal if my memory of history at school serves me right.

Hmm which came first the cigarette papers of the match?
In the U.S., it is combination of FDA/DEA and the Congress who declare what drug is illegal. For instance, it is an act of Congress which made marijuana illegal. Ectasy was declared illegal by the DEA.
Congress legislates "morality" down to the general public.

That way they get to have all the drugs and hookers for themselves.