Someone said that old masters indulged in Opium in the past. That is true but they certainly didn't do it to improve themselves, they did becasue they were addicts. The absolute truth is that internal practice requires a lessening of attatchment so that one can attain a clear, undiluted and natural grasp of the nature of the mind. Any substance of strength ingested or absorbed into the body will affect that initial reasoning. And whether it feels nice, blissful, super-sensitive and sexy, it will ultimately only do one single thing, and that is, DETRACT AND DEVIATE from ones initial quest. It will never help you along the path to internal cultivation. Thats a fact.!!Lao Tzu quotes in the Tao Te Ching " Education requires that you gain daily, the Tao requires that you lose daily". Meditation is about ridding oneself of falseness and achieving clarity of what is real. Do you honestly believe that allowing drugs into your internal cultivation you are getting closer to realisation??? To advance in this path one must ultimately when the time is right realise that drugs just like many other factors are the obvious things that need to be got rid of. If you don't feel the need to let go of them yet then you are not ready to gain realisation yet. I know this sounds terribly black and white, but it is considered to be the truth just by me but of those who have gone before us and achieved spiritual enlightenment.