Peru
Dr. de Rios has a long and distinguished career as a researcher in the area of hallucinogens and culture. She conducted fieldwork both in the North Coast of Peru and the Amazon. In the former site, an hallucinogenic cactus, San Pedro (containing mescaline) has been used for 2000 years in healing ceremonies and displayed in Moche and Nazca art of the region. She also worked in the Peruvian Amazon in Iquitos and Pucallpa, Peru, with more than a dozen traditional Mestizo folk curanderos who treated psychological and emotional disorders using the plant hallucinogen ayahuasca and other healing plants. Her books, Visionary Vine: Hallucinogenic Healing in the Peruvian Amazon and Amazon Healer: The Life and Times of an Urban Shaman as well as numerous articles emerged from this research. (see bibliography)

Brazil
Dr. de Rios was a member of an international research team, funded in part by the Heffter Foundation in Santa Fe, N.M., to conduct research on adolescent members of the União do Vegetal Church, who ingested the plant hallucinogen, ayahuasca, as part of their church's sacrament. She traveled throughout Brazil and visited 11 temples and observed the church rituals. Part of her duties was to design qualitative research and help implement focus groups on youth and drugs around that country. Neuropsychological tests showed that the U.D.V. youth compared to a control group demonstrated no significant differences in cognitive abilities or performance. The results of the study were published in the Journal of Psychoactive Drugs, Theme Issue, October 2005, "Ayahuasca: Cross-cultural Perspective." (see bibliography)