The Waorani Indians of eastern Ecuador are one of the least acculturated tribes in South America and hence provide a unique opportunity for studying the role of medicinal plants in an isolated Amazonian people. Biomedical studies conducted by a team from Stanford and Duke Universities have revealed a surprising dearth of endemic disease among recently contacted Waorani. An intensive ethnobotanical study in the spring of 1980 found a perspicacious knowledge of ethnoecology among all adult Waorani, but discovered relatively few medicinal plants. Partial results of this survey and a discussion of Waorani disease concepts are presented. The implications in terms of the origin of plant medicines among indigenous peoples are discussed. Are the Waorani unique because of their isolation or do they represent a pattern of medicinal plant use closer to the aboriginal situation before the impact of Western disease? The conclusions challenge the orthodox view of the native and the origins of his prodigious knowledge of medicinal botany.