Black Cohosh

What Is Black Cohosh?

Black cohosh is a tall woodland perennial of eastern North America, and one of the most widely used herbal remedies for menopausal symptoms. Its rhizome and roots are the medicine. They are taken mainly for hot flushes and night sweats ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}.

The plant grows in moist deciduous forests from southern Ontario to Georgia, and is especially common in the mountains ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}. Indigenous peoples of the region used it for menstruation, rheumatic pain, coughs and colds, and it later became a staple of Eclectic and Western herbal medicine ^{36,38Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →Reference 38Heeter et al. · 2021Distinguishing black cohosh from look-alikes — conservation and identification articleView study →}.

The rhizome contains more than forty triterpene glycosides, including actein and 23-epi-26-deoxyactein ^{30,33Reference 30Le et al. · 2025ReviewReview of black cohosh-induced toxicity and adverse clinical effectsView study →Reference 33ESCOP · 2011ReviewCimicifugae rhizoma (Black Cohosh)}. It has been tested in dozens of clinical trials for menopausal symptoms, with mixed results ^{1,2Reference 1Sadahiro et al. · 2023Meta-analysisBlack cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysisView study →Reference 2Leach et al. · 2012Systematic reviewBlack cohosh (Cimicifuga spp.) for menopausal symptoms — Cochrane systematic review of randomised controlled trialsView study →}.

The plant is sold under two botanical names, Cimicifuga racemosa and Actaea racemosa, which refer to the same species ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}. It is not related to blue cohosh (Caulophyllum thalictroides), a plant of the barberry family.

How Is Black Cohosh Used?

Black cohosh is used mostly during perimenopause and menopause, as a short- to medium-term remedy.

• Standardised extracts — tablets or capsules of ethanol or isopropanol rhizome extract. These are the preparations tested in most clinical trials, and the ones licensed in the EU ^{31,35Reference 31Henneicke-von Zepelin · 2017ReviewHenneicke-von Zepelin, H. H. (2017). 60 years of Cimicifuga racemosa medicinal products: clinical research milestones — review. Wien Med Wochenschr. https://pubmed.ncbi.nlm.nih.gov/28155126/View study →Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}.
• Tincture or liquid extract — of the dried rhizome, in Western herbal practice.
• Dried rhizome — as a decoction or in capsules.

Herbalists often combine it with herbs such as chaste tree, dong quai, sage or red clover in menopause formulas. One tested product pairs it with St John’s wort ^{4Reference 4Castelo-Branco et al. · 2021Meta-analysisReview & meta-analysis: isopropanolic black cohosh extract iCR for menopausal symptoms — an updateView study →}.

Traditional Uses

Western Herbal Medicine

In Western herbal medicine, black cohosh is a women’s herb for menopause, menstrual cramps and muscular tension. Traditional indications include hot flushes, night sweats, mood changes, irritability, headaches and muscular aches around the menopause.

Eclectic physicians also used it for rheumatic pain, neuralgia, coughs and nervous agitation.

Indigenous North American Medicine

Native Americans drank infusions of the plant to bring on menstruation, for rheumatic pains, coughs and colds, constipation and kidney trouble, to help babies sleep, and to promote milk flow ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}.

The Algonquian, Cherokee and Iroquois peoples used the rhizome for hives, kidney troubles, backache, constipation, colds and rheumatism ^{38Reference 38Heeter et al. · 2021Distinguishing black cohosh from look-alikes — conservation and identification articleView study →}.

Indications

• Hot flushes and night sweats [rhizome extract] ⚠Caution: Trials disagree. A 2023 meta-analysis of 22 trials found a small benefit over placebo, but the 2012 Cochrane review and two North American placebo-controlled trials found none ^1,2,6,7.
• Other menopausal symptoms [rhizome extract]
• Low mood and irritability around the menopause [rhizome extract] ⚠Caution: A 2023 meta-analysis found no significant effect on anxiety or depressive symptoms. The clearest benefit came from a product combining black cohosh with St John’s wort ^1,4.
• Menstrual cramps [rhizome; Western herbal medicine]
• Premenstrual irritability and hormonal headaches [rhizome; Western herbal medicine]
• Rheumatic pain and neuralgia [rhizome; Eclectic and Indigenous use]
• Coughs and colds [rhizome; Eclectic and Indigenous use]
• Delayed menstruation [rhizome; Indigenous use]
• Ovulation induction in PCOS, alongside clomiphene [rhizome extract] ⚠Caution: One trial reported higher pregnancy rates, but another found no effect on follicles or the womb lining, and a systematic review rated the evidence low in quality ^13,14,15.

Botany

Black cohosh is a tall perennial herb in the buttercup family, Ranunculaceae. Its smooth stems grow 75–250 cm tall ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}.

The leaves are large and divided two or three times into threes, with 20–70 sharply toothed leaflets in all. The end leaflet is usually three-lobed ^{36,37Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →Reference 37NC State Extension (n.d.)Actaea racemosa (black cohosh) — plant description — species databaseView study →}.

In summer the plant carries erect, branched spires of flowers 10–60 cm long, held well above the leaves. Each small flower has white petals about 3 mm long and 55–110 stamens, which give the spikes a fluffy look. The flowers have an unpleasant smell ^{36,37Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →Reference 37NC State Extension (n.d.)Actaea racemosa (black cohosh) — plant description — species databaseView study →}.

Each flower produces a single dry pod 5–10 mm long, holding smooth brown seeds ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}. Below ground, the plant grows from a rhizome with its roots, the part used as medicine ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}.

Distribution

Black cohosh grows in eastern North America, from southern Ontario and Massachusetts south to Georgia and west to Illinois, Missouri and Arkansas ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}. Plants found in Maine and Vermont were probably planted originally ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}.

It grows from sea level to about 1,500 m, in moist mixed deciduous forest, on wooded slopes and in ravines, along creeks and forest margins, and especially in mountainous country ^{36Reference 36RamseyRamsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379View study →}.

Black cohosh is critically imperilled in Mississippi, Massachusetts and Illinois. United Plant Savers lists it as At-Risk ^{38Reference 38Heeter et al. · 2021Distinguishing black cohosh from look-alikes — conservation and identification articleView study →}.

About 97% of the black cohosh harvest is dug from wild stands ^{38Reference 38Heeter et al. · 2021Distinguishing black cohosh from look-alikes — conservation and identification articleView study →}. Because the rhizome is the medicine, digging takes the whole plant, and a woodland perennial is slow to replace itself.

Cultivated and forest-farmed black cohosh is available. It is grown under a forest canopy in Appalachian forest-farming projects, and it is the option to ask for.

Several related Actaea species, including Asian ones, have been found as adulterants in commercial black cohosh products ^{39Reference 39Jiang et al. · 2011In vitroPhytochemical fingerprinting to thwart black cohosh adulteration: a 15 Actaea species analysis — in vitro (analytical)View study →}. When buying, it is worth asking the supplier to name the species and show how it was authenticated.

Growing Conditions

Cultivation snapshot for Black Cohosh

LifeperennialZoneUSDA 3–8

• Prefers dappled to full shade, ideally with 2–3 hours of morning sun; with too little light it may not flower ^{37Reference 37NC State Extension (n.d.)Actaea racemosa (black cohosh) — plant description — species databaseView study →}.
• Likes rich, moisture-retentive, humusy soil, much like its native forest floor ^{37Reference 37NC State Extension (n.d.)Actaea racemosa (black cohosh) — plant description — species databaseView study →}.
• Slow to establish from seed and slow to regrow after the rhizome is harvested.

Grow it yourself

Farm Wiki is our cultivation-focused sister site, also run by Justin Cooke.

How to growComing soon

Find seedsComing soon

Pharmacology & Research

Black cohosh has been tested in dozens of randomised controlled trials for menopausal symptoms, and summarised in several meta-analyses and a Cochrane review. Some meta-analyses find a modest benefit for hot flushes and overall symptoms ^{1,3,4Reference 1Sadahiro et al. · 2023Meta-analysisBlack cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysisView study →Reference 3Shams et al. · 2010Meta-analysisEfficacy of black cohosh-containing preparations on menopausal symptoms: a meta-analysis of randomised placebo-controlled trialsView study →Reference 4Castelo-Branco et al. · 2021Meta-analysisReview & meta-analysis: isopropanolic black cohosh extract iCR for menopausal symptoms — an updateView study →}. The 2012 Cochrane review found no significant difference from placebo, and two placebo-controlled North American trials were negative ^{2,6,7Reference 2Leach et al. · 2012Systematic reviewBlack cohosh (Cimicifuga spp.) for menopausal symptoms — Cochrane systematic review of randomised controlled trialsView study →Reference 6Pockaj et al. · 2006RCTPhase III double-blind, randomised, placebo-controlled crossover trial of black cohosh for hot flashes (NCCTG N01CC1)View study →Reference 7Jacobson et al. · 2001RCTRandomised trial of black cohosh for hot flashes among women with a history of breast cancerView study →}.

Most trial patients have received one product, a standardised isopropanolic extract (iCR, sold as Remifemin) ^{31Reference 31Henneicke-von Zepelin · 2017ReviewHenneicke-von Zepelin, H. H. (2017). 60 years of Cimicifuga racemosa medicinal products: clinical research milestones — review. Wien Med Wochenschr. https://pubmed.ncbi.nlm.nih.gov/28155126/View study →}. Several of the reviews of that extract were written by staff of its manufacturer ^{25,31Reference 25Naser et al. · 2011Meta-analysisSuspected black cohosh hepatotoxicity: no evidence by meta-analysis of randomised controlled trials for isopropanolic extractView study →Reference 31Henneicke-von Zepelin · 2017ReviewHenneicke-von Zepelin, H. H. (2017). 60 years of Cimicifuga racemosa medicinal products: clinical research milestones — review. Wien Med Wochenschr. https://pubmed.ncbi.nlm.nih.gov/28155126/View study →}.

The EU treats black cohosh extracts as a well-established medicine for hot flushes and sweating, while noting that neither the mode of action nor the active constituents are known ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}. Everything beyond menopausal symptoms, including bone, inflammation and cancer, rests on laboratory and animal work.

1. Menopausal Vasomotor Symptoms

This is the herb’s most-tested indication, and the evidence conflicts. A 2023 pairwise meta-analysis of 22 RCTs (n=2,310) found black cohosh extracts improved overall menopausal symptoms and hot flushes versus placebo, with small effect sizes (Hedges’ g ≈ 0.32 for hot flushes) ^{1Reference 1Sadahiro et al. · 2023Meta-analysisBlack cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysisView study →}.

An earlier meta-analysis of seven trials reported a 26% improvement in vasomotor symptoms, with significant heterogeneity between trials ^{3Reference 3Shams et al. · 2010Meta-analysisEfficacy of black cohosh-containing preparations on menopausal symptoms: a meta-analysis of randomised placebo-controlled trialsView study →}. A review of the isopropanolic extract iCR reported efficacy comparable to low-dose transdermal estradiol or tibolone ^{4Reference 4Castelo-Branco et al. · 2021Meta-analysisReview & meta-analysis: isopropanolic black cohosh extract iCR for menopausal symptoms — an updateView study →}.

The 2012 Cochrane review of 16 RCTs (n=2,027, median 40 mg/day for a mean of 23 weeks) found no significant difference from placebo in hot-flush frequency or symptom scores, and rated the quality of most trials as unclear ^{2Reference 2Leach et al. · 2012Systematic reviewBlack cohosh (Cimicifuga spp.) for menopausal symptoms — Cochrane systematic review of randomised controlled trialsView study →}.

Two placebo-controlled trials were also negative. In the NCCTG crossover trial (n=132, 20 mg twice daily), hot-flush scores fell 20% on black cohosh and 27% on placebo ^{6Reference 6Pockaj et al. · 2006RCTPhase III double-blind, randomised, placebo-controlled crossover trial of black cohosh for hot flashes (NCCTG N01CC1)View study →}. In a trial in women with a history of breast cancer (n=85), the two groups did not differ ^{7Reference 7Jacobson et al. · 2001RCTRandomised trial of black cohosh for hot flashes among women with a history of breast cancerView study →}.

A network meta-analysis for the UK’s NICE guideline found black cohosh more effective than placebo, though not significantly better than combined hormone therapy ^{5Reference 5Sarri et al. · 2017Meta-analysisVasomotor symptoms from natural menopause: a systematic review and network meta-analysis (NICE guideline)View study →}.

Gap: the positive signal is concentrated in trials and reviews of one standardised extract; independent trials are often null, and the results do not carry over to teas or non-standardised products.

2. Menopausal Mood & Neuropsychological Symptoms

Black cohosh is also used for the irritability, low mood and anxiety of the menopausal transition. The iCR review found the extract better than placebo for neurovegetative and psychological symptoms, with the largest effect when it was combined with St John’s wort (Hypericum perforatum) ^{4Reference 4Castelo-Branco et al. · 2021Meta-analysisReview & meta-analysis: isopropanolic black cohosh extract iCR for menopausal symptoms — an updateView study →}. A 2019 meta-analysis reported benefit for anxiety and depression in peri- and postmenopausal women ^{9Reference 9Shahmohammadi et al. · 2019Meta-analysisEfficacy of herbal medicines on anxiety and depression in peri- and postmenopausal women: a systematic review and meta-analysisView study →}.

A randomised trial against fluoxetine (n=120) found black cohosh reduced Kupperman-index and hot-flush scores more than the SSRI, while fluoxetine did more for depression scores ^{8Reference 8Oktem et al. · 2007RCTBlack cohosh and fluoxetine in postmenopausal symptoms: a prospective, randomised trialView study →}.

⚠ The 2023 pairwise meta-analysis found no significant improvement in anxiety (g=0.19) or depressive symptoms (g=0.41) ^{1Reference 1Sadahiro et al. · 2023Meta-analysisBlack cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysisView study →}.

Gap: mood is usually a secondary outcome in menopause trials, the results are inconsistent, and the strongest signal comes from a combination with St John’s wort, so it cannot be attributed to black cohosh alone.

3. PCOS & Ovulation Induction

A separate line of research tests black cohosh as an add-on to clomiphene citrate for ovulation induction in polycystic ovary syndrome. In a randomised trial (n=194), adding Cimicifuga racemosa to clomiphene improved endometrial thickness and hormone profiles, and clinical pregnancies per cycle were 34.8% versus 17.2% ^{13Reference 13Shahin et al. · 2014RCTAdding Cimicifuga racemosa to clomiphene induction cycles in PCOS improves cycle outcomes and pregnancy rates — randomised trialView study →}.

A 2021 systematic review found three RCTs reporting improved pregnancy rates with black cohosh plus clomiphene, and judged short-term use to appear safe. It also found several risk-of-bias concerns and a lack of high-quality evidence ^{14Reference 14Fan et al. · 2021Systematic reviewSystematic review of black cohosh for management of PCOS-related infertilityView study →}.

⚠ A separate randomised trial (n=100, 10 mg twice daily for 10 days a cycle) found no difference in follicle number or endometrial thickness when black cohosh was added to clomiphene ^{15Reference 15Pourhoseini et al. · 2022Clinical trialCimicifuga racemosa with clomiphene for ovulation induction in PCOS: a clinical trialView study →}.

Gap: the supporting trials are small, single-centre and methodologically weak; black cohosh here is an add-on to a fertility drug, not a standalone treatment.

4. Anti-Inflammatory

Low-grade inflammation rises after oestrogen loss, and cell studies suggest black cohosh extracts reduce it. A 2025 study funded by the extract’s manufacturer found the Ze 450 extract reduced nitric oxide, IL-1, IL-6, iNOS, HIF-1α and mTOR in LPS-stimulated macrophages, and shifted their metabolism from oxidative phosphorylation toward glycolysis ^{16Reference 16Günther et al. · 2025In vitroCimicifuga racemosa extract Ze 450 shifts macrophage immunometabolism and attenuates pro-inflammatory signalling — in vitroView study →}.

Bioactivity-guided fractionation earlier identified cimiracemate A as an anti-inflammatory constituent. At 140 µM it cut LPS-induced TNF-α in human macrophages by about half, through MAPK and NF-κB signalling ^{17Reference 17Yang et al. · 2009In vitroIdentification of cimiracemate A as an anti-inflammatory constituent of black cohosh on human macrophages — in vitroView study →}.

These findings are confined to cell systems.

5. Bone / Osteoporosis

Postmenopausal women lose bone, so black cohosh’s possible skeletal effect has drawn interest, with mixed preclinical results. In human osteoblasts, the isopropanolic extract raised osteoprotegerin secretion 3–5-fold and improved the OPG-to-RANKL ratio, an effect blocked by an oestrogen-receptor antagonist ^{18Reference 18Viereck et al. · 2005In vitroIsopropanolic extract of black cohosh stimulates osteoprotegerin production by human osteoblasts — in vitroView study →}.

The isolated triterpene actein stimulated osteoblastic MC3T3-E1 cells and protected them against oxidative mitochondrial damage in vitro ^{19Reference 19Lee et al. · 2014In vitroActein isolated from black cohosh promotes the function of osteoblastic MC3T3-E1 cells — in vitroView study →}. A 2025 study reported that C. racemosa, and the Asian C. foetida, improved bone microstructure in ovariectomised rats, with CB2R and ERα signalling involved ^{20Reference 20Hu et al. · 2025In vitroCimicifuga foetida and C. racemosa prevent postmenopausal osteoporosis by inhibiting osteoclast autophagy via CB2R and ERα — in vitro and ovariectomised-rat modelView study →}.

⚠ A controlled FDA study in ovariectomised rats found black cohosh extract had no effect on bone mineral density, alone or with risedronate ^{21Reference 21Inselman et al. · 2024AnimalBlack cohosh extract and risedronate coadministration on bone health in an ovariectomised rat modelView study →}.

Gap: no human bone-outcome data exist, the animal evidence conflicts, and the Cochrane review listed bone health as an unresolved question ^{2Reference 2Leach et al. · 2012Systematic reviewBlack cohosh (Cimicifuga spp.) for menopausal symptoms — Cochrane systematic review of randomised controlled trialsView study →}.

6. Anticancer (Actein)

Cell-line work suggests the triterpene glycoside actein slows cancer-cell growth. Actein preferentially inhibited breast-cancer cell growth, triggered calcium release through the ER IP3 receptor, and modulated NF-κB and MEK pathways ^{23Reference 23Einbond et al. · 2013In vitroActein induces calcium release in human breast cancer cells — in vitroView study →}.

In breast-cancer cells it acted synergistically with doxorubicin and 5-fluorouracil, and enhanced cell death from paclitaxel ^{22Reference 22Einbond et al. · 2006In vitroActein and a fraction of black cohosh potentiate antiproliferative effects of chemotherapy agents on human breast cancer cells — in vitroView study →}.

Actein isolated from the Asian Cimicifuga foetida inhibited colorectal-cancer cells and a xenograft tumour through the PI3K/Akt pathway ^{24Reference 24Yan et al. · 2021In vitroActein antagonizes colorectal cancer by blocking PI3K/Akt pathways — in vitro and xenograft modelView study →}.

The authors note that actein is lipophilic, which may limit its bioavailability ^{23Reference 23Einbond et al. · 2013In vitroActein induces calcium release in human breast cancer cells — in vitroView study →}. No whole-herb or human oncology data exist.

Gap: confined to isolated actein in cell and xenograft models.

Mechanisms

How black cohosh works is not settled, and it does not behave like a classical phytoestrogen ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}. The best-characterised lead is serotonergic. The tryptamine Nω-methylserotonin binds the 5-HT7 receptor and blocks serotonin re-uptake in vitro ^{10Reference 10Powell et al. · 2008In vitroIn vitro serotonergic activity of black cohosh and identification of Nω-methylserotonin as a potential active constituentView study →}, and the isopropanolic extract restored serotonin pathways in the brains of ovariectomised rats ^{11Reference 11Wang et al. · 2016AnimalEstradiol valerate and Remifemin ameliorate ovariectomy-induced decrease in a serotonin dorsal raphe–preoptic hypothalamus pathway in rats — animal modelView study →}.

Triterpene glycosides such as actein have been studied for tissue-selective oestrogen-receptor and CB2R signalling, and cimiracemate A for anti-inflammatory NF-κB and MAPK activity ^{17,20,32Reference 17Yang et al. · 2009In vitroIdentification of cimiracemate A as an anti-inflammatory constituent of black cohosh on human macrophages — in vitroView study →Reference 20Hu et al. · 2025In vitroCimicifuga foetida and C. racemosa prevent postmenopausal osteoporosis by inhibiting osteoclast autophagy via CB2R and ERα — in vitro and ovariectomised-rat modelView study →Reference 32Overk et al. · 2008In vitroHigh-content screening and mechanism-based evaluation of estrogenic botanical extracts (SERM-like activity of black cohosh) — in vitroView study →}.

Clinical Trials

A ClinicalTrials.gov search returned 27 registered records naming black cohosh: 14 completed, 1 recruiting, 1 active and not recruiting, 2 terminated, 2 withdrawn, and 7 of unknown status. None is planned but not yet recruiting. The one recruiting study is a multi-supplement anxiety and fibromyalgia trial that includes black cohosh among other supplements.

Last checked: July 2026.

Phytochemistry

The rhizome’s characteristic constituents are cycloartane-type triterpene glycosides, of which more than forty have been described ^{30Reference 30Le et al. · 2025ReviewReview of black cohosh-induced toxicity and adverse clinical effectsView study →}. The best known are actein, 23-epi-26-deoxyactein, the compound most commercial extracts are standardised to, and cimicifugoside ^{33,34Reference 33ESCOP · 2011ReviewCimicifugae rhizoma (Black Cohosh)Reference 34Avula et al.HPLC determination of the triterpene glycosides actein, 23-epi-26-deoxyactein and cimicifugoside in Actaea/Cimicifuga species}. The cimiracemosides belong to the same group.

The rhizome also contains more than twenty polyphenols, including the phenolic acids ferulic acid, isoferulic acid and caffeic acid, and the resin cimicifugin. It contains more than seventy nitrogen-containing compounds ^{30,33,34Reference 30Le et al. · 2025ReviewReview of black cohosh-induced toxicity and adverse clinical effectsView study →Reference 33ESCOP · 2011ReviewCimicifugae rhizoma (Black Cohosh)Reference 34Avula et al.HPLC determination of the triterpene glycosides actein, 23-epi-26-deoxyactein and cimicifugoside in Actaea/Cimicifuga species}.

Two minor constituents have been studied for specific activity. The tryptamine Nω-methylserotonin is a potent 5-HT7 ligand and serotonin re-uptake inhibitor in vitro ^{10Reference 10Powell et al. · 2008In vitroIn vitro serotonergic activity of black cohosh and identification of Nω-methylserotonin as a potential active constituentView study →}. The phenolic ester cimiracemate A is anti-inflammatory in human macrophages ^{17Reference 17Yang et al. · 2009In vitroIdentification of cimiracemate A as an anti-inflammatory constituent of black cohosh on human macrophages — in vitroView study →}.

The isoflavone formononetin has been reported in older work, but a fingerprinting study of fifteen Actaea species did not find it in any of them ^{39Reference 39Jiang et al. · 2011In vitroPhytochemical fingerprinting to thwart black cohosh adulteration: a 15 Actaea species analysis — in vitro (analytical)View study →}. The same study found that cimifugin and cimiracemoside F distinguish black cohosh from most Asian Actaea species ^{39Reference 39Jiang et al. · 2011In vitroPhytochemical fingerprinting to thwart black cohosh adulteration: a 15 Actaea species analysis — in vitro (analytical)View study →}.

Commercial products can differ markedly in composition, because of the number of constituents and the use of related species ^{30,39Reference 30Le et al. · 2025ReviewReview of black cohosh-induced toxicity and adverse clinical effectsView study →Reference 39Jiang et al. · 2011In vitroPhytochemical fingerprinting to thwart black cohosh adulteration: a 15 Actaea species analysis — in vitro (analytical)View study →}.

Constituent Summary

Triterpene glycosides make up only a few percent of the dried rhizome, and the amount varies by source ^{33,34Reference 33ESCOP · 2011ReviewCimicifugae rhizoma (Black Cohosh)Reference 34Avula et al.HPLC determination of the triterpene glycosides actein, 23-epi-26-deoxyactein and cimicifugoside in Actaea/Cimicifuga species}.

Dosage

Clinical trials use standardised extracts rather than the whole rhizome. Their doses are milligrams of extract and cannot be converted into a weight of dried herb.

Research Doses

Traditional Dosage

Western herbal practice uses the whole rhizome, tincture or liquid extract. These doses are not interchangeable with the extract doses above.

Safety & Pregnancy

Black cohosh is generally well tolerated in short- to medium-term use. Its one serious concern is rare liver injury, and EU guidance sets out warnings for liver disease, breast cancer and oestrogen use ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}.

Full Safety & Interactions Detail

Liver. Liver injury, including hepatitis, jaundice and abnormal liver tests, has been linked with black cohosh products, at an unknown frequency ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}. Case reports include cholestatic liver injury that resolved after the herb was stopped ^{29Reference 29Brar et al. · 2021Case reportCholestatic drug-induced liver injury associated with black cohosh — case reportView study →}, and liver failure that required a transplant, described as the fifth such case ^{28Reference 28Lim et al. · 2013Case reportSubacute liver failure secondary to black cohosh leading to liver transplantation — case reportView study →}.

A US Pharmacopeia review of 30 case reports rated every one as a “possible” rather than a probable or certain cause, and recommended a caution on product labels ^{27Reference 27Mahady et al. · 2008Case reportUnited States Pharmacopeia review of the black cohosh case reports of hepatotoxicityView study →}. A pooled analysis of five trials of the isopropanolic extract, by authors from its manufacturer, found no effect on liver enzymes over 3–6 months ^{25Reference 25Naser et al. · 2011Meta-analysisSuspected black cohosh hepatotoxicity: no evidence by meta-analysis of randomised controlled trials for isopropanolic extractView study →}. A systematic review of adverse events found that all 13 clinical trials it identified pointed to relative safety, and that causality was hard to establish in most case reports ^{26Reference 26Borrelli et al. · 2008Systematic reviewBlack cohosh (Cimicifuga racemosa): a systematic review of adverse eventsView study →}.

EU guidance says people with a history of liver disorder should use black cohosh with caution. Anyone taking it should stop and see a doctor at signs of liver injury: tiredness, loss of appetite, yellowing of the skin or eyes, severe upper stomach pain with nausea and vomiting, or dark urine ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}.

Breast cancer and oestrogens. EU guidance says people treated for breast cancer or another hormone-dependent tumour should not use black cohosh without medical advice, and that it should not be combined with oestrogens unless a doctor advises it. In one mouse study the extract increased lung metastases, though not primary breast tumours ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}. A review of the isopropanolic extract found no effect on breast or endometrial tissue in trials ^{4Reference 4Castelo-Branco et al. · 2021Meta-analysisReview & meta-analysis: isopropanolic black cohosh extract iCR for menopausal symptoms — an updateView study →}.

Other effects. Digestive upset, allergic skin reactions and swelling of the face and limbs have been reported ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}. A 2025 review describes an aneugenic mode of genotoxicity for black cohosh extract ^{30Reference 30Le et al. · 2025ReviewReview of black cohosh-induced toxicity and adverse clinical effectsView study →}. A doctor should be consulted about any vaginal bleeding during use ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}.

Drug metabolism. In healthy volunteers, 28 days of black cohosh did not meaningfully change CYP1A2, CYP2D6, CYP2E1 or CYP3A4 activity ^{40Reference 40Gurley et al. · 2005RCTIn vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes — randomised study in healthy volunteersView study →}. A 7% dip in CYP2D6 activity was judged too small to matter clinically ^{40Reference 40Gurley et al. · 2005RCTIn vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes — randomised study in healthy volunteersView study →}. In 16 healthy volunteers, 14 days of black cohosh did not change blood levels of digoxin, a test drug for the P-glycoprotein drug pump ^{41Reference 41Gurley et al. · 2006RCTEffect of milk thistle (Silybum marianum) and black cohosh (Cimicifuga racemosa) supplementation on digoxin pharmacokinetics in humans — randomised study in healthy volunteersView study →}.

Antidepressants. A review of adverse-event reports linked black cohosh taken with antidepressants to restless legs (with mianserin), breast enlargement and pain (with paroxetine) and low blood sodium (with venlafaxine) ^{42Reference 42Siwek et al. · 2023ReviewHarder, better, faster, stronger? Retrospective chart review of adverse events of interactions between adaptogens and antidepressant drugsView study →}. The mechanism was not measured, and EU guidance lists no reported interactions ^{35Reference 35Committee on Herbal Medicinal Products · 2018ReviewEuropean Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monographView study →}.

References

1. Sadahiro, R., et al. (2023). Black cohosh extracts in women with menopausal symptoms: an updated pairwise meta-analysis. Menopause. https://pubmed.ncbi.nlm.nih.gov/37192826/
2. Leach, M. J., & Moore, V. (2012). Black cohosh (Cimicifuga spp.) for menopausal symptoms — Cochrane systematic review of randomised controlled trials. Cochrane Database Syst Rev. https://pubmed.ncbi.nlm.nih.gov/22972105/
3. Shams, T., et al. (2010). Efficacy of black cohosh-containing preparations on menopausal symptoms: a meta-analysis of randomised placebo-controlled trials. Altern Ther Health Med. https://pubmed.ncbi.nlm.nih.gov/20085176/
4. Castelo-Branco, C., et al. (2021). Review & meta-analysis: isopropanolic black cohosh extract iCR for menopausal symptoms — an update. Climacteric. https://pubmed.ncbi.nlm.nih.gov/33021111/
5. Sarri, G., et al. (2017). Vasomotor symptoms from natural menopause: a systematic review and network meta-analysis (NICE guideline). BJOG. https://pubmed.ncbi.nlm.nih.gov/28276200/
6. Pockaj, B. A., et al. (2006). Phase III double-blind, randomised, placebo-controlled crossover trial of black cohosh for hot flashes (NCCTG N01CC1). J Clin Oncol. https://pubmed.ncbi.nlm.nih.gov/16782922/
7. Jacobson, J. S., et al. (2001). Randomised trial of black cohosh for hot flashes among women with a history of breast cancer. J Clin Oncol. https://pubmed.ncbi.nlm.nih.gov/11352967/
8. Oktem, M., et al. (2007). Black cohosh and fluoxetine in postmenopausal symptoms: a prospective, randomised trial. Adv Ther. https://pubmed.ncbi.nlm.nih.gov/17565936/
9. Shahmohammadi, A., et al. (2019). Efficacy of herbal medicines on anxiety and depression in peri- and postmenopausal women: a systematic review and meta-analysis. Post Reprod Health. https://pubmed.ncbi.nlm.nih.gov/31630610/
10. Powell, S. L., et al. (2008). In vitro serotonergic activity of black cohosh and identification of Nω-methylserotonin as a potential active constituent. J Agric Food Chem. https://pubmed.ncbi.nlm.nih.gov/19049296/
11. Wang, W., et al. (2016). Estradiol valerate and Remifemin ameliorate ovariectomy-induced decrease in a serotonin dorsal raphe–preoptic hypothalamus pathway in rats — animal model. Ann Anat. https://pubmed.ncbi.nlm.nih.gov/27562857/
12. Drewe, J., Boonen, G., & Culmsee, C. (2022). Treat more than heat — new therapeutic implications of Cimicifuga racemosa through AMPK-dependent metabolic effects — review. Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/35338990/
13. Shahin, A. Y., & Mohammed, S. A. (2014). Adding Cimicifuga racemosa to clomiphene induction cycles in PCOS improves cycle outcomes and pregnancy rates — randomised trial. Gynecol Endocrinol. https://pubmed.ncbi.nlm.nih.gov/24592984/
14. Fan, C. W., Cieri-Hutcherson, N. E., & Hutcherson, T. C. (2021). Systematic review of black cohosh for management of PCOS-related infertility. J Pharm Pract. https://pubmed.ncbi.nlm.nih.gov/33926292/
15. Pourhoseini, S. A., et al. (2022). Cimicifuga racemosa with clomiphene for ovulation induction in PCOS: a clinical trial. Avicenna J Phytomed. https://pubmed.ncbi.nlm.nih.gov/35145891/
16. Günther, M., et al. (2025). Cimicifuga racemosa extract Ze 450 shifts macrophage immunometabolism and attenuates pro-inflammatory signalling — in vitro. Biomed Pharmacother. https://pubmed.ncbi.nlm.nih.gov/40382826/
17. Yang, C. L., et al. (2009). Identification of cimiracemate A as an anti-inflammatory constituent of black cohosh on human macrophages — in vitro. J Med Chem. https://pubmed.ncbi.nlm.nih.gov/19835377/
18. Viereck, V., et al. (2005). Isopropanolic extract of black cohosh stimulates osteoprotegerin production by human osteoblasts — in vitro. J Bone Miner Res. https://pubmed.ncbi.nlm.nih.gov/16234977/
19. Lee, Y. S., & Choi, E. M. (2014). Actein isolated from black cohosh promotes the function of osteoblastic MC3T3-E1 cells — in vitro. J Med Food. https://pubmed.ncbi.nlm.nih.gov/24552231/
20. Hu, S. J., et al. (2025). Cimicifuga foetida and C. racemosa prevent postmenopausal osteoporosis by inhibiting osteoclast autophagy via CB2R and ERα — in vitro and ovariectomised-rat model. Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/40680333/
21. Inselman, A. L., et al. (2024). Black cohosh extract and risedronate coadministration on bone health in an ovariectomised rat model. Front Pharmacol. https://pubmed.ncbi.nlm.nih.gov/38689663/
22. Einbond, L. S., et al. (2006). Actein and a fraction of black cohosh potentiate antiproliferative effects of chemotherapy agents on human breast cancer cells — in vitro. Planta Med. https://pubmed.ncbi.nlm.nih.gov/16988912/
23. Einbond, L. S., et al. (2013). Actein induces calcium release in human breast cancer cells — in vitro. Fitoterapia. https://pubmed.ncbi.nlm.nih.gov/23939423/
24. Yan, L., et al. (2021). Actein antagonizes colorectal cancer by blocking PI3K/Akt pathways — in vitro and xenograft model. Anticancer Drugs. https://pubmed.ncbi.nlm.nih.gov/33929996/
25. Naser, B., et al. (2011). Suspected black cohosh hepatotoxicity: no evidence by meta-analysis of randomised controlled trials for isopropanolic extract. Menopause. https://pubmed.ncbi.nlm.nih.gov/21228727/
26. Borrelli, F., & Ernst, E. (2008). Black cohosh (Cimicifuga racemosa): a systematic review of adverse events. Am J Obstet Gynecol. https://pubmed.ncbi.nlm.nih.gov/18984078/
27. Mahady, G. B., et al. (2008). United States Pharmacopeia review of the black cohosh case reports of hepatotoxicity. Menopause. https://pubmed.ncbi.nlm.nih.gov/18340277/
28. Lim, T. Y., et al. (2013). Subacute liver failure secondary to black cohosh leading to liver transplantation — case report. BMJ Case Rep. https://pubmed.ncbi.nlm.nih.gov/23833086/
29. Brar, H. S., & Marathi, R. (2021). Cholestatic drug-induced liver injury associated with black cohosh — case report. BMJ Case Rep. https://pubmed.ncbi.nlm.nih.gov/33962922/
30. Le, Y., et al. (2025). Review of black cohosh-induced toxicity and adverse clinical effects. J Environ Sci Health C Toxicol Carcinog. https://pubmed.ncbi.nlm.nih.gov/40503925/
31. Henneicke-von Zepelin, H. H. (2017). 60 years of Cimicifuga racemosa medicinal products: clinical research milestones — review. Wien Med Wochenschr. https://pubmed.ncbi.nlm.nih.gov/28155126/
32. Overk, C. R., et al. (2008). High-content screening and mechanism-based evaluation of estrogenic botanical extracts (SERM-like activity of black cohosh) — in vitro. Comb Chem High Throughput Screen. https://pubmed.ncbi.nlm.nih.gov/18473738/
33. ESCOP (2011). Cimicifugae rhizoma (Black Cohosh). ESCOP Monographs, 2nd ed. Supplement.
34. Avula, B., et al. HPLC determination of the triterpene glycosides actein, 23-epi-26-deoxyactein and cimicifugoside in Actaea/Cimicifuga species.
35. Committee on Herbal Medicinal Products (2018). European Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma — revision 1 (EMA/HMPC/48745/2017) — regulatory monograph. European Medicines Agency. https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-cimicifuga-racemosa-l-nutt-rhizome-revision-1_en.pdf
36. Ramsey, G. W. (n.d.). Cimicifuga racemosa (Linnaeus) Nuttall — species description, habitat and distribution — flora. In Flora of North America Editorial Committee (eds.), Flora of North America North of Mexico, Vol. 3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500379
37. NC State Extension (n.d.). Actaea racemosa (black cohosh) — plant description — species database. North Carolina Extension Gardener Plant Toolbox. https://plants.ces.ncsu.edu/plants/actaea-racemosa/
38. Heeter, K. J., Price, L., & Brosi, S. (2021). Distinguishing black cohosh from look-alikes — conservation and identification article. United Plant Savers. https://unitedplantsavers.org/distinguishing-black-cohosh-from-look-alikes/
39. Jiang, B., Ma, C., Motley, T., Kronenberg, F., & Kennelly, E. J. (2011). Phytochemical fingerprinting to thwart black cohosh adulteration: a 15 Actaea species analysis — in vitro (analytical). Phytochemical Analysis, 22(4), 339–351. https://pubmed.ncbi.nlm.nih.gov/21337649/
40. Gurley, B. J., Gardner, S. F., Hubbard, M. A., et al. (2005). In vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes — randomised study in healthy volunteers. Clin Pharmacol Ther. https://pubmed.ncbi.nlm.nih.gov/15900287/
41. Gurley, B. J., Barone, G. W., Williams, D. K., et al. (2006). Effect of milk thistle (Silybum marianum) and black cohosh (Cimicifuga racemosa) supplementation on digoxin pharmacokinetics in humans — randomised study in healthy volunteers. Drug Metab Dispos. https://pubmed.ncbi.nlm.nih.gov/16221754/
42. Siwek, M., Woroń, J., Wrzosek, A., et al. (2023). Harder, better, faster, stronger? Retrospective chart review of adverse events of interactions between adaptogens and antidepressant drugs. Frontiers in Pharmacology. https://pubmed.ncbi.nlm.nih.gov/37829299/

View all 42 references▾