Refugees and immigrants experience complex stressors from the process of immigration that can have lasting and severe long-term mental health consequences. Ayahuasca is a natural plant-based psychoactive brew traditionally used in ceremonies throughout the Western Amazon basin. Experiences after ayahuasca ingestion are often likened to intense psychotherapy, leading ayahuasca to have strong potential as a treatment for trauma and related disorders. However, data on the health impact of naturalistic ceremonial ayahuasca use is limited. The current longitudinal study was conducted to gather prospective data on ceremonial ayahuasca use in a group of primarily female immigrants and refugees and to provide further insight into the patterns and outcomes surrounding that use. Our findings revealed ceremonial use of ayahuasca is associated with significant and persisting improvements in mental health, well-being, and psychological functioning, as well as notable positive behavioral changes lasting at least 3-4 months following ingestion.