Any question answered...

I used to drink it in tea when I was a nipper. Didn't realise it was what they make mephawhatever out of. But salvia is the way to go in terms of legal highs...

mephedrone isn't made from khat, the khat just contains the active agent cathinone, which is related to the group of amphetamine compounds (ie, mephedrone). Mephedrone, as a compound, does not exist on its own, it has to be synthesised in a lab.