Prophet Muhammad (sallallahu alaihi wa sallam) is reported to have warned:

"Every intoxicant (e.g. drugs, alcohol) is forbidden. A person who consumes an intoxicant, 40 days of his salaat (prayer) is lost." (not accepted by Allah) [Abu Dawud v2 P518]

Don’t be deceived that a small quantity of drugs, which may be non-intoxicating, is acceptable. Rasulullah (sallallahu alaihi wa sallam) declared:

"Every intoxicant - a large quantity and a small quantity - is haraam (forbidden)." [Ibid]