Coca is a plant in the family Erythroxylaceae, native to north-western South America. The plant plays a significant role in traditional Andean culture. Coca, spelled koka in Quechua and Aymara, resembles a blackthorn bush, and grows to a height of 2–3 m (7–10 ft). The branches are straight, and the leaves, which have a green tint, are thin, opaque, oval, and taper at the extremities. A marked characteristic of the leaf is an areolated portion bounded by two longitudinal curved lines, one line on each side of the midrib, and more conspicuous on the under face of the leaf.
Coca leaves have been used for centuries as a stimulant. Pre-Incan Indians used the leaves to relieve altitude sickness (hypoxia), hunger and fatigue. Coca is traditionally cultivated in the lower altitudes of the eastern slopes of the Andes, or the highlands depending on the species grown. Since ancient times, its leaves have been an important trade commodity between the lowlands where it is grown and the higher altitudes where it is widely consumed by the Andean peoples of Peru, Colombia, Ecuador, Venezuela, and Bolivia.
Traces of coca have been found in mummies dating to 3000 years ago. Extensive archeological evidence for the chewing of coca leaves dates back at least to the sixth century A.D. Moche period, and the subsequent Inca period, based on mummies found with a supply of coca leaves, pottery depicting the characteristic cheek bulge of a coca chewer, spatulas for extracting alkali and figured bags for coca leaves and lime made from precious metals, and gold representations of coca in special gardens of the Inca in Cuzco. Coca chewing may originally have been limited to the eastern Andes before its introduction to the Incas.