Newton KM et al. (2006) Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trial. Ann Intern Med 145: 869–879

Vasomotor symptoms (daytime hot flashes and night sweats) are among the most common nuisances caused by the hormonal changes that occur in the menopause. Hormone-replacement therapy can have adverse effects, and alternative treatments—such as herbal remedies based on the plant black cohosh (Cimicifuga racemosa)—have become increasingly popular. Newton and colleagues at Group Health in Seattle, Washington, compared the effects of hormone-replacement therapy, three regimens of black cohosh, and placebo, on vasomotor symptoms in a 1-year, randomized, double-blind study.

In total, 351 women aged 45–55 years who were in late menopausal transition or postmenopausal and were having at least two vasomotor symptoms per day were randomly assigned to one of five treatments: black cohosh 160 mg per day; 'multibotanical' (200 mg black cohosh daily plus nine other herbal ingredients); multibotanical and dietary counseling on soya foods; hormone-replacement therapy; or placebo, for 1 year. The frequency and severity of vasomotor symptoms were measured at baseline and 3, 6 and 12 months after enrollment.

The study found no significant differences between the effect of herbal treatments and that of placebo on vasomotor symptoms, with one exception: patients receiving multibotanical plus dietary counseling for 12 months had more-severe symptoms than the placebo group. Hormone-replacement therapy, however, resulted in a significant amelioration of vasomotor symptoms compared with placebo. The authors conclude that black cohosh, used alone or in multibotanical products, does not provide an effective alternative to hormone-replacement therapy for treating vasomotor symptoms in menopausal women.