Hallucinations occur during what doctors call psychosis, but they can also manifest outside the corridors of what is considered sick and dysfuctional. They can occur across a broad spectrum of non-ordinary changes in perception and play an important role in spiritual and creative arts around the world. At the virtual opposite space to hospitals and biomedical contexts, indigenous groups in the Americas voluntarly seek hallucinations by drinking psychoactive brews such as ayahuasca . In such types of shamanic contexts, hallucinations are valued as social, religious, and theraputic aspects of life. But are the hallucinations described by users of psychiatric services similar to those perceived by Amazonian shamans? By considering these two different types of experience side-by-side, we can learn something about how people and culture attribute sickness to non-ordinary types of perception, whether auditory, visual, or other sensory twists. There is also another special difference I would like to highlight. As psychologist Richard Noll indicated, the ability to control hallucinations appears to be one of the main tasks of being a shaman. Learning how shamans and others work to control hallucinations can likely help us better understand and treat psychosis. My goal in this article is to explore such a possiblity. Shamans and the Quest to Control Ayahuasca Visions Ayahuasca In contrast to contemporary Euro-American societies, many cultures value hallucinations and place them at the heart of social life. Historical and ethnographic studies have documented the importance of hallucinations in Native American societies and the wide variety of techniques that can be used to induce them, such as fasting, isolation, sensory deprivation, or the use of psychotropic substances. Hallucinogenic plants such as ayahuasca occupy a central place in the life of some Amazonian societies, as do peyote and psilocybin mushrooms in the Mesoamerican region, or San Pedro cactus in the Andean world.