A randomized double-blind, placebo- controlled multi-center, study appearing in the journal Obstetrics and Gynecology(2005; 105(5 Pt 1)) tested the efficacy of a standardized black cohosh extract on menopausal symptoms. The subjects were 304 women with menopausal symptoms. They were given a standardized extract of black cohosh (5mg isopropanolic extract) for a period of 12 weeks. The supplement was found to significantly reduce menopausal symptoms. The group receiving the supplement experienced improvement of symptoms as scored by the Menopause Rating Scale. The supplement seemed especially effective in treating hot flashes.