Cocaine is a powerfully addictive stimulant that directly affects the brain.
There are basically two chemical forms of cocaine: hydrochloride salt and freebase. The hydrochloride salt, or powdered form of cocaine, dissolves in water and, when abused, can be taken intravenously (by vein) or intra-nasally (in the nose). Freebase refers to a compound that has not been neutralized by an acid to make the hydrochloride salt. The freebase form of cocaine is smokable.
Information provided by the National Institutes of Health.