What is the Catholic Church's position on recreational marijuana use? Several US states have passed voter initiatives to allow recreational marijuana use for adults.  What is the Catholic Church’s official position on this issue?
Under Respect for health in Catechism of the Catholic Church, 2291 the Church teaches


  The use of drugs inflicts very grave damage on human health and
  life. Their use, except on strictly therapeutic grounds, is a grave
  offense. Clandestine production of and trafficking in drugs are
  scandalous practices. They constitute direct co-operation in evil,
  since they encourage people to practices gravely contrary to the moral
  law.


Thus the recreational use marijuana, considered a drug, would not be permissible.

And from the Vatican?


  Other churches take more of a hard-line approach to marijuana. The
  Catholic Church says that drugs "constitute direct co-operation in
  evil" and does not seem to make exceptions for marijuana. The Vatican
  has condemned legalizing "soft drugs" like marijuana, and its
  newspaper, L'Osservatore Romano, recently scolded Italian lawmakers
  for liberalizing pot-possession laws. - Source: What Would Jesus
  Smoke? By Torie Bosch | Slate.


Please see also: 


A real cure and prevention | On the campaigns to legalize drugs | L'Osservatore Romano, June 9, 2011.



  In this health emergency, the attempt to muddy the waters by
  classifying as a drug everything from wine to LSD is pathetic. So is
  the attempt to say that one need only know how to take them in
  moderation, without remembering that wine is a food nutrient and
  tobacco does not make you lose your head, but marijuana does. We are
  the first to be scandalized by the early consumption of tobacco and
  alcohol by young people and we ask for strong restrictions for youth
  and a clear campaign to dissuade binge drinking or the use of
  nicotine, but this does not mean that one needs to add a third
  disaster to the first two, especially at a time when the first two are
  showing signs of success.



And the first link below where Pope Francis is quoted as condemning the legalization of marijuana.




Please see also: 


Pope Francis condemns legalization of marijuana | Google search.
AMERICA/URUGUAY - The legalization of marijuana will destroy family.
To Puff or Not to Puff, by NISSA LAPOINT | NCR.