The aim of this study was to evaluate the safety and efficacy of the finished herbal product TMN-1 in the treatment of menopausal symptoms in climacteric women. A multicentre, prospective, observational follow-up study was conducted in four hospitals in Taiwan. One hundred and twenty-six women were included who were aged 45 to 55 years, experienced hot flushes and did not receive hormone replacement therapy. Women were excluded if they had any signs of active cancer. All participants received TMN-1 treatment 4 g, three times per day, for 12 weeks. Significant improvement in scores of hot flushes and Kupperman index (KI) were found at weeks 4 and 12 in the 50 periand 53 postmenopausal women (82%) who completed the study (P < 0.001). Logistic regression analyses showed that perimenopausal women with hot flushes had sevenfold (95% CI 1.8 to 28.0) odds of improvement in favour of treatment, whereas that of the post-menopausal group was 1.5 (95% CI 0.5 to 4.2). Further analyses showed that TMN-1 produced superior benefit in women with moderate and severe menopausal symptoms (KI±21) compared to those with mild symptoms. It also improved symptoms of insomnia, nervousness, melancholia and palpitation in perimenopausal women. Five adverse drug reactions were detected: three single events of nausea, abdominal pain and abdominal fullness; and two events of diarrhoea.