In reaction to medical cannabis access referendums on the ballots in Arizona and California, former presidents Gerald Ford, Jimmy Carter, and George Bush signed a letter stating that they ``categorically oppose'' access to cannabis for its many proven therapeutic uses such as the prevention of blindness and epileptic seizures [1]. Their chief concern was that legal medical access would send the message that cannabis is safe. The presidents can, however, lay their safety concerns to rest because the scientific literature overwhelmingly confirm ....