The deadliest side effect of medical marijuana is the message being sent to our kids, the lie that marijuana use is safe. So it is imperative that we do not send that message. We must do our jobs to educate them as to the real facts and trust them to make the right decision. Prache Cream For some time now, people have known the medical uses of marijuana. There are some who believe that marijuana has been used for more than 12,000 years already. In fact, the National Institute of Health (NIH) has already released detailed reports of the possible medical uses of marijuana last February 1997.