Everything can be bad at some level, but Ma Huang turns deadly at unpredictable levels.
Here's an interesting thing about marijuana - http://www.hort.purdue.edu/newcrop/ncnu02/v5-284.html - part of Purdue University's new crop series. *My alma mater University of Mississippi grows the government's stash and I used to walk past one of their fields to get to school. *It had a tall fence and the friendliest guard dog I've ever known. *I was told the serious production happened at a more isolated and secure field.