Cocaine is a highly addictive stimulant derived from the coca plant, which is grown primarily in Bolivia, Peru, and Colombia. Since the 1880s, cocaine has been used in eye, nose, and throat surgeries as a local anesthetic for its ability to constrict blood vessels and limit bleeding. In many countries these are the only legal uses of the drug today.

Cocaine (benzoylmethylecgonine) is a central nervous system stimulant, a vasoconstrictor, an appetite suppressant, and a local anesthetic producing effects similar to other "caine" drugs (novocaine, benzocaine, lidocaine etc.). Specifically, it is a serotonin–norepinephrine–dopamine reuptake inhibitor, which mediates functionality of these neurotransmitters. Because of the way it affects the mesolimbic dopamine reward pathway, cocaine has a significant addictive liability and is therefore illegal in most countries for non-medical uses.

Crack is cocaine hydrochloride powder that has been processed to form a rock crystal that is then usually smoked. The term “crack” refers to the crackling sound produced by the rock as it is heated.

The crack form of cocaine affects the user much more rapidly than cocaine that is snorted, making it more addictive than cocaine for most users. When crack cocaine is smoked, it usually takes less than 20 seconds to reach the brain, giving the user a rapid, intense feeling of euphoria.