Coca plants are the only natural source of the alkaloid cocaine and related compounds. For several thousand years, the leaves of the coca plant have been used by South American Indians as a mild stimulant, a remedy for medical problems, and for ritualistic or religious purposes. Coca chewing reduces hunger and increases endurance. It also eases the nausea, dizziness, and headaches associated with altitude sickness and relieves the symptoms of various stomach ailments. From pre-Columbian times coca has been an integral part of Andean cultures, and the commerce of coca leaves is still a legal and accepted practice in Peru and Bolivia.

The extraction and purification of cocaine hydrochloride from coca leaves, first accomplished in the mid-1800s, yields a drug with very different pharmacological effects than those associated with traditional coca chewing. Recreational use of cocaine produces a quick sense of euphoria and heightened awareness. Its use...