The two distinct methods of cocaine chewing practiced by the Indians of South America for centuries involve toasting the coca leaves and chewing them along with an alkaline material and mixing the powder made from toasted coca leaves with the ashes of other burned leaves. Although the behavioral and medical safety of chronic coca leaf chewing is controversial, it is much safer than pure cocaine administered by more efficient routes. It is clear that the obsessive self-destructive addiction risk of cocaine increases with purity and the efficiency of administration. Methods of administration include oral, intranasal, intravenous, and smoking intrapulmonary. The crucial elements that determine addiction risk are the change in the feeling state, the degree of change, the speed of onset of the change, the duration of the change, and the postdrug effects. Cocaine is less addictive if the dose is small, the peak plasma levels are low, the onset of activity is slow, the duration of action is long, and the unpleasant withdrawal effects are absent or very mild. Tables and 16 references