The notion that any authority can determine what a sovereign human being can and cannot ingest into their own body is the very essence of control. Banning any substance from responsible adult consumption no matter how harmful should simply not be permitted in a free society.
However, certain substances are deemed so harmful by "experts" that they claim to adversely affect society as a whole and thus they're banned from the population. Of course, force of laws with guns and jails have never been able to eliminate their use throughout history. So, as a practical matter, banning any substance from society always tends to do more harm than good.