A drug is any substance other than food, that when inhaled, injected, smoked, consumed, absorbed via a patch on the skin or dissolved under the tongue causes a physiological change in the body. Certain drugs, like caffine and ibuprofen, are used everyday as a medication, or as something else. Other drugs, like crystal meth and cocaine, are considered to be dangerous and lethal. Overdosing, or ODing, is when you take too many drugs and someone's bodily finctions shutdown.
I think that drugs should only be used as a medical application, not for pleasure.