The authors assessed 23 subjects immediately before and six months (27.5 weeks) after their first ayahuasca experience in an urban Brazilian religious setting, either Santo Daime (N = 1 5) or Uniao do Vegetal (N = 8). Measures included scores on instruments assessing psychiatric symptoms, personality variables and quality of life. Independent variables were the frequency of ayahuasca use throughout the period and the length of ayahuasca wash-out after six months. Santo Daime subjects had a significant reduction of minor psychiatric symptoms, improvement of mental health, and a change in attitude towards more confidence and optimism. The Uniao do Vegetal group had a significant decrease in physical pain, and attitude change towards more independence. Independence was positively correlated with the frequency of ayahuasca use and negatively correlated with the wash-out period. We discuss possible mechanisms by which these changes may occur and suggest areas for future research. Keywords- ayahuasca, mental health, psychometric, religion