Cocaine, the most potent stimulant of natural origin, is extracted from the leaves of the coca plant (Erythroxylon coca), which is indigenous to the Andean highlands of South America. Natives in this region chew or brew coca leaves into a tea for refreshment and to relieve fatigue similar to the customs of chewing tobacco and drinking tea or coffee.

Pure cocaine was first isolated in the 1880s and used as a local anesthetic in eye surgery. It was particulary useful in surgery of the nose and throat because of its ability to provide anesthesia as well as to constrict blood vessels and limit bleeding. Many of its therapeutic applications are now obsolete due to the development of safer drugs.

Illicit cocaine is usually distributed as a white crystaline powder or as an off-white chunky material. The powder, usually cocaine hydrochloride, is often diluted with a variety of substances, the most common of which are sugars such as lactose, inositol and mannitol, and local anesthetics such as lidocaine. The adulteration increases the volume and thus multiplies profits. Cocaine hydrochloride is generally snorted or dissolved in water and injected. It is rarely smoked.

"Crack," the chunk or "rock" form of cocaine, is a ready-to-use freebase. On the illicit market it is sold in small, inexpensive dosage units that are smoked. With crack came a dramatic increase in drug abuse problems and violence. Smoking delivers large quantities of cocaine to the lungs, producing effects comparable to intravenous injection; these effects are felt almost immediately after smoking, are very intense, and are quickly over. Once introduced in the mid-1980s, crack abuse spread rapidly and made the cocaine experience available to anyone with $10 and access to a dealer. In addition to other toxicities associated with cocaine abuse, cocaine smokers suffer from acute respiratory problems including cough, shortness of breath, and severe chest pains with lung trauma and bleeding.

The intensity of the psychological effects of cocaine, as with most psychoactive drugs, depends on the dose and rate of entry to the brain. Cocaine reaches the brain through the snorting method in three to five minutes. Intravenous injection of cocaine produces a rush in 15 to 30 seconds and smoking produces an almost immediate intense experience. The euphoric effects of cocaine are almost indistinguishable from those of amphetamine, although they do not last as long. These intense effects can be followed by a dysphoric crash. To avoid the fatigue and the depression of "coming down," frequent repeated doses are taken. Excessive doses of cocaine may lead to seizures and death from respiratory failure, stroke, cerebral hemorrhage or heart failure. There is no specific antidote for cocaine overdose.

According to the 1993 Household Drug Survey, the number of Americans who used cocaine within the preceding month of the survey numbered about 1.3 million; occasional users (those who used cocaine less often than monthly) numbered at approximately 3 million, down from 8.1 million in 1985. The number of weekly users has remained steady at around a half million since 1983.