THC is the psychotropic component in cannabis that gives you an intoxicating feeling of being “high”. It is also a federally scheduled or controlled substance. CBD is a non-psychotropic component in cannabis.  CBD is not a federally controlled supplement. You do not need a doctor’s recommendation or special license to purchase it. However, most patients benefit from using THC and CBD together as they are more effective treating symptoms than when they are taken individually.  This is known as the “Entourage Effect”.