In an open clinical trial, 15 patients diagnosed with DSM-IV dysthymic disorder were treated with GS-02, a herbal formulation containing extracts of four Indian herbs: Ashvatha, Kapikachu, Dhanvayasa, and Bhuriphali. Twelve patients completed the study. The medication was very well-tolerated. Among treatment completers, three (25%) patients showed no response, two (16.7%) showed partial response, and seven (58.3%) showed good response; these response rates are similar to what can be expected from an allopathic antidepressant trial. In an intent- to-treat analysis, significant improvement was observed on Hamilton depression ratings as well as on global measures. The results of this preliminary study encourage further clinical investigation of the GS-02 formulation.