Actaea racemosa

Taxonomy

The species has a history of taxonomic uncertainty. Carl Linnaeus originally placed it in the genus Actaea based on inflorescence and seed morphology. Thomas Nuttall later reclassified it to Cimicifuga due to its dry follicles. Recent morphological and gene phylogeny analyses show it is more closely related to Actaea species, leading to the revision back to Actaea racemosa. Blue cohosh (Caulophyllum thalictroides), despite a similar common name, belongs to the family Berberidaceae and is not closely related.

Description

Black cohosh is a smooth herbaceous perennial with large, compound leaves from an underground rhizome. Basal leaves are tripinnately compound with serrated margins. Flowers appear in late spring and early summer on tall stems, forming racemes of 55–110 white stamens with no petals or sepals; they have a sweet, fetid smell that attracts flies, gnats, and beetles. The fruit is a dry follicle containing several seeds.

Cultivation

This perennial thrives in consistently moist, heavy soil. Its tall, tapering spikes of white flowers bloom in midsummer on thin black-purple stems, releasing a medicinal scent that earned it the name Bugbane. The seed heads remain attractive for weeks. Deeply cut leaves, burgundy in the variety atropurpurea, resemble maple foliage. It is a popular garden plant, winning the Royal Horticultural Society's Award of Garden Merit and being named Virginia's 2017 wildflower of the year.

Traditional and alternative medicine

Native Americans used black cohosh in the belief it could treat gynecological and other disorders. It appeared in the U.S. Pharmacopoeia under the name black snakeroot in 1830, and in the 19th century the root was used for snakebite, inflamed lungs, and pain from childbirth. Extracts from the rhizome and root contain triterpene saponins, triterpene glycosides such as actein, and cimifugic acids. Black cohosh products have regulatory approval as herbal medicines across much of Europe, as well as in China, Malaysia, Thailand, Argentina, and several other countries, ensuring consistent quality, safety, and effectiveness for menopausal symptoms like hot flushes and excessive sweating.

In the United States and India, it is used as a dietary supplement for menopausal symptoms and other gynecological problems. Meta-analyses support these claims only for products with official marketing authorization. There is a lack of long-term safety information. Adverse reactions include allergic skin reactions, facial and peripheral edema, and gastrointestinal symptoms.

Black cohosh does not show harmful effects on endometrium or breast cancer survivors, but such studies have not been published for dietary supplements. Most material is wild-harvested, and adulteration is a quality concern. Very high doses may cause nausea, dizziness, visual effects, lower heart rate, and increased perspiration.