This paper is based on more than three decades’ worth of practical work, research and teaching in clinical psychology, as well as research into Traditional Indigenous Medicine (TIM) in South America. Firstly, it provides a comprehensive review of the main findings from a number of different research projects and poses new empirical possibilities, and addresses the need to delve deeper into a first and third person investigative process. Secondly, the paper reports on a preliminary research to assess to what extent participant experience expanded states of consciousness from the diets and ingestion of plants in an indigenous context. This is done using a questionnaire called VEEC (Validación de Experiencias en Estados de Consciencia –Validation of Experiences in States of Consciousness), a newly devised instrument specifically for this purpose. Future lines of research are also put forward, for the proper introduction of TIM into professional medical practice.