Black cohosh: an alternative therapy for menopause?

Due to the long-term health risks now associated with hormone replacement therapy, many menopausal women are actively seeking alternative treatments. One such alternative is black cohosh (Actaea racemosa, syn. Cimicifuga racemosa), which has been used in the United States for the treatment of gynecologic complaints for more than 100 years. Review of the published clinical data suggests that black cohosh may be useful for the treatment of menopausal symptoms, such as hot flashes, profuse sweating, insomnia, and anxiety. Results from the most recently published trial, however, indicate that black cohosh is not effective for the treatment of menopausal symptoms in breast cancer survivors being treated with tamoxifen. Because the overall quality of the published clinical trials is low, two new randomized, double-blind, placebo-controlled clinical trials are currently underway in the United States. To date, only one standardized black cohosh extract has been tested clinically; the current recommended dose is 40-80 mg per day. At least 4-12 weeks of treatment may be required before any therapeutic benefits may be apparent. Adverse reactions such as nausea, vomiting, headaches, dizziness, mastalgia, and weight gain have been observed in clinical trials. No drug interactions are reported in the medical literature. The estrogenic effects of black cohosh are controversial, and the more recent data indicate that black cohosh extracts may have an anti-estrogenic activity. Owing to potential effects on sex hormones, however, black cohosh should not be administered to children or during pregnancy and lactation.