Show me a quote where it says it is OK to smoke marijuana.
Show me any quote from any Catholic source where the use of any stupefactants at all is recommended or condoned.
Pius IX, Leo XIII, and Pius X all used tobacco. It seems they didn't know that it was dangerous but I think they should have not used it because it's unnecessary pleasure.
http://books.google.com/books?id=5GoAAAAAYAAJ&pg=PA250&dq=pius+x+tobacco&lr=&ei=j857Sff8ForONeuE5awE#PPA250,M1"Unlike many of his brothers, he [St. Pius X] does not disdain the use of tobacco ; he is passionately fond of music, and is himself a musician who, with the aid of his close friend, the famous composer Perosi, may be expected to effect considerable revival of Church music."
http://books.google.com/books?id=fCwEjf8hotAC&pg=PA146&dq=#v=onepage&q=&f=falseDuring the Pope's [Leo XIII] recent illness, the doctors thought it their duty to prohibit him from snuff-taking. The illustrious patient suffered keenly from this deprivation. The times have greatly changed since Urban VIII and Innocent X vigorously proscribed tobacco, the former Pope going so far as to threaten to excommunicate any one who might take a pinch of snuff within the precincts of the Vatican. The brief issued on the 1st February, 1659, by Innocent X against the use of tobacco was abrogated on the 16th January, 1725, by Benedict XIII, for very good and sufficient reasons. Like Benedict XIII, Leo XIII takes snuff in large quantities, and
it is well known that Pius IX used to smoke. A snuff-taking Pope after a smoking Pope! Tobacco is restored to favour in the Church.