This review article focuses on the on-going use of plant hallucinogens, especially various Banisteriopsis species, among contemporary aboriginal populations of Ecuador. It surveys the evidence of prehistoric ayahuasca use by interpretations of Ecuadorian archaeological remains, and surveys in detail the use and belief systems connected to major plant hallucinogenic use among the Jibaro Indians and other tribal groups. A secondary theme includes coastal and Inter-Andean aboriginal drug use. The article stresses the inter-relatedness of aboriginal belief systems, folk medicine and world view linked to plant hallucinogenic ingestion.