The efficacy and tolerability of a single-agent treatment with 7.5 g/day Gosha-jinki-gan in Japanese females with overactive bladder were analyzed objectively with linguistically validated questionnaires. A total of 44 Japanese females diagnosed as having overactive bladder were enrolled. Before and after the treatment, urinary frequency during the daytime and sleep was counted for two days, and the International Prostate Symptom Score index scores and quality of life index scores were examined. The efficacy assessment was done by comparing the quality of life index scores. The total scores of International Prostate Symptom Score, quality of life index scores and urinary frequency during the daytime and sleep were significantly decreased, respectively. Objective evaluation with the quality of life questionnaire yielded a result of excellent in 7%, improved in 46%, unchanged in 41% and worsened in 7%. Adverse reactions were observed in 9%. Gosha-jinki-gan could be a safe and effective potential therapeutic alternative in females with overactive bladder.