Randomised controlled trials (RCTs) that compared mono preparations of black cohosh with placebo or standard drug treatment in women who experienced menopausal symptoms were eligible for inclusion. Women who had undergone a hysterectomy were considered eligible if at least one ovary remained. Women with medically induced menopause were excluded.
The included trials were set in Germany, Czech Republic, USA, Switzerland and China. Populations included perimenopausal and postmenopausal women whose ages ranged between 46 and 58 years, where reported. Reported outcomes included severity of symptoms rating scales (Kupperman Menopausal Index, Wiklund menopause symptoms index, menopausal ratings scale) and self-reported frequency of vaso-motor symptoms. Dosage of black cohosh preparations varied across studies. Half of the included trials used a commercial preparation called Remifemin.
Studies were selected by two independent reviewers. Disagreements were resolved by discussion.