I just want to say that although I obviously (from my other comment) support the use of psychedelics for therapeutic use, I would be careful about saying "in small to medium doses these drugs are not harmful at all." Years ago in college, my brother took a "medium" dose of mushrooms and it was an extremely bad experience for him. He went into a very scared state and ended up having to leave school for the rest of that semester. He was in a semi-psychotic state for three months. His reaction was not typical; normally a bad trip ends and you're ok. But it's not unheard of by any means. I understand now that it may have been the chaotic setting in which he took the mushrooms that triggered the bad reaction. But why it lasted that long in his case, I don't know. So, at the least, don't do it unless you're with people you can really trust. And if you're looking to do it for truly therapeutic reasons -- to see if it can help with stuttering or related severe anxiety -- I would really (really) recommend you do it the way I talk about in my other comment -- with "sitters" who are not taking the drug themselves. This would definitely take research and work to arrange with the right people. But if you're truly doing not just to have fun and see what happens, it can make all the difference. I spent ten months researching this to try to help a friend with crippling social anxiety.