There's been a thread similar to this before:
Drugs and their illegalityThe so called soft drugs should be decriminalised without question (in my opinion). i.e Ecstacy, LSD, GHB, 'shrooms' Marijuana etc. Why Mescaline is illegal is completely beyond me, I can't find a single potential harm in using mescaline if used responsibly, and even irresponsible use could yield very minor repercussions.
As adults, we should be able to do what we wish as long as we do not harm anyone else in the process. I can't believe the government has the nerve to tell us what we can and cannot experience inside our own heads, in the privacy of our own homes, where we are no risk to anyone other than ourselves, and even the danger the user poses to him/herself is very, very questionable. They cross the line when they tell me what my mind can and cannot experience when I am zero risk to anyone else - regardless of whether or not I'd want the experience. It's like skydiving, yeah there's a potential danger, but when used correctly it could be a worthwhile experience - and society should not see it as anything different when it comes to the 'soft' drugs in particular.