© 2015 Taylor & Francis Group, LLC.Objective: We aimed to investigate the effects of Maras powder (smokeless tobacco) on treatment outcomes of patients with anxiety.Method: Patients between 18 and 65 years old diagnosed as generalized anxiety disorder and anxiety disorder not otherwise specified were enrolled. The patients were categorized into two groups: Maras powder using group (30 patients) and Maras powder free group (30 patients). All the participants were administered the Turkish version of Hospital Anxiety and Depression Scale (HADS) at baseline and the 1 and 2 months after the treatment. All patients were given standard pharmacological treatments for their psychiatric diagnosis.Results: There was a significant decrease of HADS scores within the groups after treatment. The mean baseline HADS scores of both groups were not significantly different. However, mean HADS scores of the groups were significantly different at the first and second months after the treatment.Conclusion: Maras powder use may negatively affect the treatment of anxiety disorders.