Herbal Monograph

Black cohosh

Actaea racemosa L.

Ranunculaceae

Class 2b Hormonal modulator Anti-inflammatory Antispasmodic Nervine

Premier women's herb for menopausal symptoms — works via serotonergic, not es...

Overview

Plant Description

Actaea racemosa is a large, clump-forming herbaceous perennial growing 100–250 cm tall from a thick, knotty, dark brown to black rhizome with numerous fibrous roots. The rhizome has a characteristic bitter, acrid taste. Leaves are large (up to 1 m), ternately decompound (divided into 3s repeatedly), with sharply serrate, ovate leaflets 5–12 cm long. The inflorescence is a striking terminal raceme 15–60 cm long, densely packed with small, white, petal-less flowers consisting primarily of numerous stamens, giving the racemes a feathery, bottle-brush appearance. Flowering occurs June–September. Flowers have a strong, sweetish, unpleasant odor (the specific epithet 'cimicifuga' means 'bug repeller'). Fruit is a dry follicle containing flattened seeds that rattle when ripe (hence 'rattletop').

Habitat

Native to rich, moist deciduous forests of eastern North America. Grows in deep shade to partial shade on rich, humus-rich, well-drained woodland soils. Found at elevations from 200–1,500 m. Associates with beech-maple and mixed mesophytic forests. Prefers slightly acidic to neutral soils (pH 5.0–7.0) with high organic matter content. Requires consistent moisture but does not tolerate waterlogged conditions.

Distribution

Endemic to eastern North America, from southern Ontario south through the Appalachian region to Georgia and Alabama, west to Missouri and Arkansas. Greatest abundance in the central and southern Appalachian Mountains. Wild populations are under significant harvesting pressure. The species is considered 'at risk' by United Plant Savers. Commercial cultivation is increasing in Germany, North America, and New Zealand to reduce wild-harvesting pressure.

Parts Used

Rhizome and root (Cimicifugae rhizoma)

Preferred: Standardized extract (isopropanolic or ethanolic extract standardized to triterpene glycosides); also used as tincture or decoction

The dried rhizome with attached roots is the official drug in all pharmacopeial monographs (Commission E, WHO, AHP, EMA, BHP). Contains the therapeutically active triterpene glycosides (actein, 23-epi-26-deoxyactein, cimicifugoside) and phenolic compounds (caffeic acid esters, fukinolic acid). The whole rhizome extract demonstrates pharmacological activity not attributable to any single isolated compound, suggesting synergistic action among multiple constituents.

Key Constituents

Triterpene glycosides (Cycloartane type)

Actein (27-deoxyactein) Major triterpene glycoside; standardized extracts contain approximately 1–2 mg per dose
23-epi-26-Deoxyactein Major triterpene glycoside
Cimicifugoside Present in rhizome
Cimiracemoside A–F Multiple related compounds present

The triterpene glycosides are considered the primary active constituents. They do NOT act as direct phytoestrogens (no binding to classical estrogen receptors ERα/ERβ at pharmacologically relevant concentrations). Current evidence suggests they modulate menopausal symptoms primarily through serotonergic mechanisms (binding to 5-HT1A, 5-HT1D, and 5-HT7 receptors) and possibly through dopaminergic activity. This is a critical distinction: black cohosh does not raise serum estrogen levels and does not stimulate estrogen-dependent tissues.

Phenolic acids and esters

Fukinolic acid Characteristic constituent
Cimicifugic acids A, B, E, F Present in rhizome
Caffeic acid and isoferulic acid Minor

The phenolic acid fraction may contribute to the overall estrogenic-modulating and anti-inflammatory activity of the extract. Some researchers propose that the phenolic acids, not the triterpenes, are responsible for the weak estrogenic activity observed in some assays. The interaction between the triterpene and phenolic fractions likely produces the clinical effect through multiple complementary mechanisms.

Alkaloids

Nω-Methylserotonin (NMS) Trace
Cimipronidine Trace

The presence of Nω-methylserotonin supports the serotonergic hypothesis for black cohosh's mechanism of action in hot flash reduction. Serotonin plays a key role in thermoregulation, and serotonergic drugs (SSRIs, SNRIs) also reduce hot flashes.

Other compounds

Tannins (condensed) Approximately 2–4%
Resins Approximately 15–20% of crude rhizome
Volatile oils Trace

Secondary constituents with limited direct therapeutic significance. The resinous fraction was historically important in Eclectic medicine preparations.

Herbal Actions

hormonal-modulator (primary)

Modulates menopausal symptoms through serotonergic and possibly dopaminergic mechanisms rather than direct estrogenic activity. Does NOT bind significantly to classical estrogen receptors (ERα, ERβ) at physiological concentrations. Does NOT stimulate estrogen-dependent tissues (breast, endometrium) in clinical studies. May act as a selective estrogen receptor modulator (SERM) in some tissues. Commission E approved for 'premenstrual discomfort, dysmenorrhea, and climacteric neurovegetative complaints.'

[1, 2, 5, 12]
Anti-inflammatory (secondary)

Reduces inflammation

Triterpene glycosides and phenolic acids demonstrate anti-inflammatory activity including inhibition of TNF-α, IL-6, and NF-κB pathways. Cimicifugic acid B is a notable TNF-α inhibitor. This action contributes to musculoskeletal pain relief and possibly to modulation of neuroinflammation underlying vasomotor symptoms.

[12]
Antispasmodic (secondary)

Relieves smooth muscle spasm

Relaxes smooth muscle, particularly uterine muscle. Historically valued by Eclectic physicians for uterine cramping and dysmenorrhea. The mechanism involves inhibition of calcium influx in smooth muscle cells. Commission E includes dysmenorrhea among approved indications.

[1, 9, 10]
Nervine (secondary)

Supports and calms the nervous system

Anxiolytic and mild sedative activity attributed to serotonergic modulation (binding to 5-HT receptors) and possible GABAergic effects. Clinical trials show improvement in anxiety and mood disturbance as part of the menopausal symptom complex. The Eclectics valued it as a 'nerve tonic' for nervous excitability and restlessness.

[9, 12]
antirheumatic (mild)

Traditional use for rheumatic and arthritic pain, particularly in Native American and Eclectic traditions. Anti-inflammatory activity of triterpene glycosides provides pharmacological support. Less commonly used for this indication in modern practice.

[9, 10, 13]

Therapeutic Indications

reproductive-female

well established

Menopausal vasomotor symptoms (hot flashes, night sweats)

The primary modern indication. Commission E approved for 'climacteric neurovegetative complaints.' WHO monograph supports use for vasomotor symptoms of menopause. Multiple RCTs and meta-analyses demonstrate significant reduction in hot flash frequency and severity compared to placebo. The standardized isopropanolic extract (Remifemin/iCR) has the strongest clinical evidence base, with >60 years of clinical use and >12,000 patients in clinical trials. EMA approved as well-established traditional use.

[1, 2, 3, 5, 6]
supported

Menopausal mood disturbance (anxiety, irritability, sleep disruption)

Clinical trials show improvement in psychological menopausal symptoms (Kupperman Index, Menopause Rating Scale) including anxiety, irritability, depressive mood, and sleep disturbance. The serotonergic mechanism is consistent with anxiolytic and mood-stabilizing effects. Not a substitute for antidepressant therapy in clinical depression.

[2, 6, 12]
well established

Dysmenorrhea (painful menstruation)

Commission E approved for 'dysmenorrhea.' The antispasmodic action on uterine smooth muscle reduces cramping pain. Historically one of the primary indications in both Native American and Eclectic medicine.

[1, 9, 13]
traditional

Premenstrual syndrome (PMS)

Commission E approved for 'premenstrual discomfort.' Traditional use for PMS-related irritability, mood swings, breast tenderness, and cramping. Limited controlled trial data specifically for PMS as distinct from menopausal symptoms.

[1, 9]

Musculoskeletal System

traditional

Rheumatic and arthritic pain

Traditional use in Native American and Eclectic medicine for rheumatism, myalgia, and neuralgia. BHP lists for 'muscular and rheumatic pain.' Anti-inflammatory triterpene glycosides provide pharmacological rationale. Less commonly prescribed for this indication in contemporary practice.

[9, 10, 13]

nervous-system

supported

Nervous tension and anxiety (especially menopausal)

Serotonergic activity supports anxiolytic effects. Clinical improvement in anxiety scores documented in multiple menopausal symptom trials. The Eclectics valued it for 'nervous excitability, restlessness, and mental depression associated with uterine disorders.'

[9, 12]

Energetics

Temperature

cool

Moisture

dry

Taste

bitteracrid

Tissue States

hot/excitation, wind/tension

Black cohosh is cooling and somewhat drying. The intensely bitter, acrid taste reflects the triterpene and resinous constituents. In Western energetic terms, it addresses hot, tense tissue states — the flushing, irritability, and nervous tension associated with menopause. Hoffmann describes it as 'cooling the fire' of menopausal heat while simultaneously relaxing nervous tension. The Eclectic tradition emphasized its 'alterative' quality — gradually shifting the body's terrain from a state of excess heat and tension toward balance.

Traditional Uses

Native American Medicine

  • Gynecological complaints including difficult menstruation, labor facilitation, and postpartum recovery (Cherokee, Iroquois, Algonquin)
  • Rheumatic and arthritic pain (Delaware, Cherokee)
  • Snakebite remedy (the common name 'black snakeroot' reflects this use)
  • Kidney disorders and general malaise
  • Sore throat — root decoction used as gargle

"Black cohosh was one of the most important medicinal plants of multiple Native American nations. The Cherokee used the root decoction for rheumatism, kidney troubles, malaise, and gynecological conditions. The Delaware used it for rheumatism. The Iroquois used it to facilitate labor and for general 'female complaints.' The name 'cohosh' derives from an Algonquin word meaning 'rough' (referring to the knotty rhizome)."

[11]

Eclectic Medicine (19th–early 20th century American)

  • Uterine tonic and antispasmodic for dysmenorrhea, amenorrhea, and difficult labor
  • Rheumatism and neuralgia — especially combined with uterine disorders
  • Nervous excitability, restlessness, and hysteria
  • Chorea (St. Vitus' dance)
  • Tinnitus and headache of neurological origin

"King's American Dispensatory (1898): 'Macrotys is one of our most valuable indigenous remedies...its range of action is wide, though centering chiefly upon the female reproductive organs and the nervous system. It is a powerful relaxant and nervine...it relieves pain dependent on a nervous origin.' John King first championed its use in Eclectic practice in the 1840s. The Eclectics considered it specific for 'muscular pain with nervous irritability, especially when associated with uterine disorders.'"

[9, 10]

European Phytotherapy (Modern)

  • Menopausal vasomotor symptoms (hot flashes, night sweats)
  • Menopausal neuropsychological symptoms (mood disturbance, anxiety, sleep problems)
  • Dysmenorrhea and premenstrual complaints
  • Alternative to hormone replacement therapy (HRT) for mild-moderate menopausal symptoms

"Black cohosh entered European practice in the mid-20th century, primarily through German phytomedicine. The standardized isopropanolic extract (Remifemin) has been available in Germany since 1956 and has accumulated over 60 years of clinical use data. Mills & Bone (2013): 'Cimicifuga is the key herbal remedy for the management of menopausal symptoms.'"

[8, 12]

Modern Research

meta analysis

Menopausal symptoms — meta-analysis

Meta-analyses of RCTs evaluating black cohosh extract for menopausal vasomotor and psychological symptoms.

Findings: Shams et al. (2010) meta-analysis of RCTs found that black cohosh significantly reduced the Kupperman Menopausal Index (KMI) score compared to placebo (weighted mean difference -1.98, 95% CI: -3.44 to -0.52, p=0.008). Borrelli & Ernst (2008) systematic review of 6 RCTs found that the evidence for black cohosh in menopausal symptoms was 'encouraging but not convincing' due to heterogeneity in preparations and outcome measures. The isopropanolic extract (iCR/Remifemin) had the most consistent positive results across trials.

Limitations: Heterogeneity in extracts used (isopropanolic vs. ethanolic vs. crude preparations), doses, treatment durations, and outcome measures across trials. Some trials had small sample sizes. The strongest evidence is specifically for the isopropanolic extract at 40 mg/day.

[5, 6]

narrative review

Mechanism of action — serotonergic vs. estrogenic

The mechanism of action remains debated but has shifted from a purely estrogenic hypothesis toward a serotonergic/neuroendocrine model.

Findings: Early hypotheses proposed direct estrogenic activity, but subsequent rigorous studies demonstrated: (1) No binding to ERα or ERβ at pharmacologically relevant concentrations, (2) No increase in serum estradiol, FSH, or LH in clinical studies, (3) No stimulation of endometrial proliferation or mammographic breast density. Current evidence favors serotonergic mechanisms: triterpene glycosides and Nω-methylserotonin bind to 5-HT1A, 5-HT1D, and 5-HT7 receptors. This is pharmacologically plausible since SSRIs/SNRIs also effectively treat hot flashes via serotonergic thermoregulation pathways in the hypothalamus.

Limitations: The exact molecular targets and binding affinities are still being characterized. Multiple mechanisms may operate simultaneously. Some in vitro data show SERM-like activity of phenolic acid fractions that may not translate to in vivo effects.

[5, 12]

narrative review

Safety — hepatotoxicity signal

Post-marketing case reports of hepatotoxicity have been a significant safety concern since 2002, prompting regulatory review.

Findings: Approximately 83 case reports of hepatotoxicity (including 4 cases requiring liver transplantation) were reported worldwide by 2006, leading to regulatory alerts from EMA, MHRA, Health Canada, and TGA. However, systematic assessment found: (1) Most cases lacked adequate causality assessment, (2) Many involved concurrent hepatotoxic medications or pre-existing liver disease, (3) The estimated incidence was approximately 1:170,000 (very rare), (4) The WHO-UMC causality assessment rated most cases as 'possible' or 'unlikely.' The EMA HMPC concluded in 2018 that the benefit-risk profile remains positive when used at recommended doses for ≤6 months, with the addition of liver function warnings.

Limitations: Case reports cannot establish causality. Confounding factors (concurrent medications, alcohol use, pre-existing liver disease) were present in most cases. Adulteration with Asian Actaea/Cimicifuga species containing different hepatotoxic compounds has been documented and may explain some cases.

[3, 7]

systematic review

Breast cancer safety

Critical safety question: does black cohosh stimulate estrogen-sensitive breast tissue?

Findings: Multiple lines of evidence indicate black cohosh does NOT stimulate breast tissue: (1) No increase in mammographic breast density in clinical studies, (2) No stimulation of MCF-7 breast cancer cell proliferation in vitro (and inhibition in several studies), (3) Retrospective epidemiological data suggesting reduced breast cancer risk in users, (4) A prospective study showing no increased breast cancer recurrence in survivors using black cohosh. The German BfArM and the North American Menopause Society (NAMS) do not consider breast cancer a contraindication, though the EMA recommends caution.

Limitations: No prospective RCTs specifically powered for breast cancer endpoints. Long-term safety data beyond 12 months is limited. Individual case variation may exist.

[5, 12]

Preparations & Dosage

Standardized Extract

Strength: 4.5–8.5:1 drug-extract ratio (DER); standardized to 1 mg triterpene glycosides per 20 mg tablet

The standardized isopropanolic extract (iCR, marketed as Remifemin) is the most extensively studied preparation. Produced via isopropanol-water extraction of the dried rhizome, standardized to triterpene glycoside content. This specific extract has >60 years of clinical use and the majority of positive clinical trial data.

Adult:

40 mg daily of standardized extract (equivalent to 1 mg triterpene glycosides calculated as 27-deoxyactein), as a single dose or divided into 2 × 20 mg

Frequency:

Once or twice daily

Duration:

Commission E recommends limiting use to 6 months without medical supervision. EMA concurs. If symptoms recur after discontinuation, consult a healthcare provider before restarting.

Pediatric:

Not indicated for children

The 40 mg/day dose of the isopropanolic extract is the most evidence-based dosing. Higher doses have not demonstrated superior efficacy. Onset of action is typically 4–8 weeks; maximum benefit may not be seen until 12 weeks. Not all commercial black cohosh products use the isopropanolic extract — ethanolic extracts, crude powders, and tinctures have different phytochemical profiles and less clinical evidence.

[1, 2, 3]

Tincture

Strength: 1:10 in 60% ethanol (BHP); or 1:5 in 60% ethanol

Tincture of dried black cohosh rhizome in 60% ethanol. Used in Western herbalist practice, though less well-studied than the standardized extract.

Adult:

1–2 mL of 1:10 tincture (60% ethanol) two to three times daily; or 0.5–1 mL of 1:5 tincture

Frequency:

Two to three times daily

Duration:

Limit to 6 months without practitioner supervision

Pediatric:

Not indicated

Tincture is the traditional preparation in Western herbalism. The high alcohol percentage is needed to extract the resinous and triterpene constituents. Less clinical evidence compared to the standardized extract. Often combined with other hormonal-modulating herbs (vitex, dong quai, sage) in menopausal formulas.

[9, 13]

Decoction

Strength: 1:125 to 1:250

Simmer 1–2 g of dried, cut rhizome in 250 mL water for 15–20 minutes. Strain. The decoction has a bitter, acrid taste.

Adult:

1–2 g dried rhizome per cup, 3 times daily

Frequency:

Three times daily

Duration:

Limit to 6 months

Pediatric:

Not indicated

Traditional preparation. The bitter taste can be ameliorated with honey. Less commonly used in modern practice due to the availability of standardized extracts and the difficulty of consistent dosing with decoctions.

[9, 13]

Safety & Interactions

Class 2b

Not to be used during lactation (AHPA Botanical Safety Handbook)

Contraindications

absolute Known hypersensitivity to Actaea racemosa or Ranunculaceae family

Avoid in individuals with documented allergy.

relative Pre-existing liver disease or hepatic impairment

Due to rare but documented hepatotoxicity case reports, patients with pre-existing liver disease should avoid black cohosh or use only under medical supervision with liver function monitoring. EMA requires a liver warning on product labeling.

Drug Interactions

Drug / Class Severity Mechanism
Tamoxifen (Selective estrogen receptor modulators (SERMs)) theoretical Theoretical concern that black cohosh could interfere with tamoxifen's anti-estrogenic effects. However, clinical evidence does not support estrogenic stimulation by black cohosh, and one study found no increase in breast cancer recurrence in tamoxifen users taking black cohosh.
Hepatotoxic medications (statins, acetaminophen, methotrexate) (Various hepatotoxic drugs) moderate Additive hepatotoxic potential. Given the rare hepatotoxicity signal, concurrent use with other hepatotoxic drugs may increase risk.
Hormone replacement therapy (HRT) (Estrogens and progestogens) minor Black cohosh may have additive effects with HRT on menopausal symptoms. No evidence of dangerous pharmacological interaction since black cohosh does not increase serum estrogen.

Pregnancy & Lactation

Pregnancy

possibly unsafe

Lactation

insufficient data

AHPA Class 2b: 'Not to be used during pregnancy and lactation.' Commission E does not explicitly contraindicate pregnancy but does not recommend use during pregnancy. The historical use by Native Americans and Eclectics included labor facilitation, suggesting uterotonic activity. Due to potential uterotonic effects and insufficient safety data, avoid during pregnancy except under qualified practitioner supervision in late-stage labor. No data on excretion into breast milk.

Adverse Effects

uncommon Gastrointestinal complaints (nausea, stomach upset, diarrhea) — Most commonly reported side effect. Generally mild and transient. Taking with food may reduce incidence.
uncommon Headache — Reported in clinical trials at rates similar to or slightly above placebo.
rare Dizziness and vertigo — Occasional reports. Usually mild and transient.
rare Weight gain — Reported in some clinical trials. Mechanism unclear.
very-rare Hepatotoxicity (liver injury) — Estimated incidence approximately 1:170,000. Approximately 83 case reports worldwide by 2006, with causality poorly established in most. Four cases required liver transplantation. EMA requires liver warning on labeling. Monitor for signs of liver injury.

References

Monograph Sources

  1. [1] Blumenthal, M., Busse, W.R., Goldberg, A., et al.. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines — Cimicifugae rhizoma. American Botanical Council / Integrative Medicine Communications (1998) . ISBN: 978-0-9655555-0-0
  2. [2] World Health Organization. WHO Monographs on Selected Medicinal Plants, Volume 2: Rhizoma Cimicifugae Racemosae. World Health Organization, Geneva (2002) . ISBN: 978-92-4-154537-8
  3. [3] European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). European Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma. EMA/HMPC/600717/2007 Rev. 1 (2018)
  4. [4] Gardner, Z., McGuffin, M. (eds.). American Herbal Products Association's Botanical Safety Handbook, 2nd Edition. CRC Press (2013) . ISBN: 978-1-4665-1695-3

Clinical Studies

  1. [5] Borrelli, F., Ernst, E.. Black cohosh (Cimicifuga racemosa) for menopausal symptoms: a systematic review of its efficacy. Pharmacological Research (2008) ; 58(1) : 8–14 . DOI: 10.1016/j.phrs.2008.05.008 . PMID: 18585461
  2. [6] Shams, T., Setia, M.S., Hemmings, R., McCusker, J., Sewitch, M., Ciampi, A.. Efficacy of black cohosh-containing preparations on menopausal symptoms: a meta-analysis. Alternative Therapies in Health and Medicine (2010) ; 16(1) : 36–44 . PMID: 20085176
  3. [7] Teschke, R., Schwarzenboeck, A., Schmidt-Taenzer, W., Wolff, A., Hennermann, K.H.. Herb induced liver injury presumably caused by black cohosh: a survey of initially purported cases and herbal quality specifications. Annals of Hepatology (2011) ; 10(3) : 249–259 . PMID: 21677326
  4. [8] Beer, A.M., Neff, A.. 60 years of Cimicifuga racemosa medicinal products: Clinical research milestones, current study findings and current development. Wiener Medizinische Wochenschrift (2013) ; 163(9–10) : 217–226 . DOI: 10.1007/s10354-016-0537-z . PMID: 28155126

Traditional Texts

  1. [9] Hoffmann, D.. Medical Herbalism: The Science and Practice of Herbal Medicine. Healing Arts Press (2003) . ISBN: 978-0-89281-749-8
  2. [10] Felter, H.W., Lloyd, J.U.. King's American Dispensatory, 18th Edition. Ohio Valley Company (1898)
  3. [11] Moerman, D.E.. Native American Ethnobotany. Timber Press (1998) . ISBN: 978-0-88192-453-4

Pharmacopeias & Reviews

  1. [12] Mills, S., Bone, K.. Principles and Practice of Phytotherapy: Modern Herbal Medicine, 2nd Edition. Churchill Livingstone / Elsevier (2013) . ISBN: 978-0-443-06992-5
  2. [13] British Herbal Medicine Association. British Herbal Pharmacopoeia. BHMA (1996) . ISBN: 978-0-903032-09-5

Last updated: 2026-03-02 | Status: review

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Full botanical illustration of Actaea racemosa L.

Public domain, American Medicinal Plants (Plate 11), Cimicifuga racemosa, via Wikimedia Commons