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Black cohosh
Black cohosh — what the European monograph actually supports, what it is not for, the form and how long it is meant to be used, side effects, and the 2 medicine interactions documented for it.
This is a reference page, not a diagnosis and not a prescription. Herbal products are real pharmacology: they have effects, side effects and interactions with medicines. Tell your doctor and your pharmacist everything you take, including teas and supplements, and never stop or change a prescribed medicine because of anything you read here.
What it is
Actaea racemosa L. (syn. Cimicifuga racemosa) — rhizome and root (Cimicifugae racemosae rhizoma)
Grouped here under Joints, urinary tract and hormones. Regulatory position: EU herbal monograph — traditional use, with a mandatory liver warning.
What the evidence supports
The registered indication: Relief of menopausal complaints such as hot flushes and profuse sweating.
Black cohosh is the most widely used non-hormonal herbal option for hot flushes, and the one carrying a regulator-mandated liver warning on the pack. The herbal committee at the European Medicines Agency reviewed reports of liver injury associated with black cohosh products and required them to warn users to stop and see a doctor if signs of liver damage appear — unusual tiredness, yellowing of the skin or eyes, dark urine, upper abdominal pain, loss of appetite. Cases are rare and causality in many of the reports is uncertain, but the warning stands and it is the single most important thing to know before starting. On efficacy, the trials for hot flushes are mixed; a traditional-use registration does not imply proven benefit, and it is not a hormone, not a treatment for osteoporosis, and not a substitute for a conversation about menopause options.
C — Traditional use only Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it.
What it is not for
Osteoporosis prevention, vaginal dryness, or vaginal bleeding of unknown cause — which always needs investigating first.
Form, strength and how long
Standardised dry extracts of the rhizome in tablets and drops. Species substitution with Asian Actaea species has been documented in commercial products, which is one argument for buying registered medicines rather than unregulated supplements.
Duration. Monograph texts limit continuous use without medical advice; anyone using it for months should be doing so with a doctor who knows.
No gram figure appears on this page on purpose. The plant part, the extraction solvent and the drug-to-extract ratio together define a preparation, and a number taken from one does not describe another. The reasoning is set out on the hub; the amount that applies to you is the one printed on the pack you are holding, and a pharmacist will read it with you.
Side effects
Stomach upset, rash, headache and weight gain are reported. The important one is liver injury, rare but the reason for the label warning.
Who should avoid it
Adults only, and not in pregnancy or breastfeeding. Anyone with liver disease should avoid it. Anyone with a history of breast cancer or on hormone-sensitive cancer treatment should not start it without the oncology team.
Interactions with medicines
| Medicine or substance | What is described |
|---|---|
| Anything else that stresses the liver | Combining it with anything else that stresses the liver — other implicated botanicals, heavy alcohol, medicines with a known hepatic signal — stacks a risk that is already the reason for the warning on the box. |
| Cancer and hormone-blocking treatment | Anyone on tamoxifen or another hormone-sensitive cancer treatment should not add it without their oncology team's agreement. The interaction question is unsettled; the stakes are not. |
The reverse view — start from the medicine rather than the plant — is in the medicine, food and alcohol interactions reference, and summarised for every herb on this site.
Sources: European Medicines Agency — Committee on Herbal Medicinal Products (HMPC), European Union herbal monographs · NIH National Center for Complementary and Integrative Health — herb fact sheets · checked 2026-09-06
Frequently asked questions
What is black cohosh used for?
Relief of menopausal complaints such as hot flushes and profuse sweating. Black cohosh is the most widely used non-hormonal herbal option for hot flushes, and the one carrying a regulator-mandated liver warning on the pack. The herbal committee at the European Medicines Agency reviewed reports of liver injury associated with black cohosh products and required them to warn users to stop and see a doctor if signs of liver damage appear — unusual tiredness, yellowing of the skin or eyes, dark urine, upper abdominal pain, loss of appetite. Cases are rare and causality in many of the reports is uncertain, but the warning stands and it is the single most important thing to know before starting. On efficacy, the trials for hot flushes are mixed; a traditional-use registration does not imply proven benefit, and it is not a hormone, not a treatment for osteoporosis, and not a substitute for a conversation about menopause options.
Does black cohosh work?
Graded C here: Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it. Osteoporosis prevention, vaginal dryness, or vaginal bleeding of unknown cause — which always needs investigating first.
How much black cohosh should I take?
This reference does not print gram figures, because they do not transfer between preparations of different extract strength. What can be said honestly is the form and the duration: Standardised dry extracts of the rhizome in tablets and drops. Species substitution with Asian Actaea species has been documented in commercial products, which is one argument for buying registered medicines rather than unregulated supplements. Monograph texts limit continuous use without medical advice; anyone using it for months should be doing so with a doctor who knows.
What are the side effects of black cohosh?
Stomach upset, rash, headache and weight gain are reported. The important one is liver injury, rare but the reason for the label warning.
Does black cohosh interact with medicines?
Yes — documented for Liver load, Cancer treatment. Each one is described on this page, with a link to the medicine-side reference where one exists.
Others in joints, urinary tract and hormones
Nettle
Leaf: to increase the amount of urine and so flush the urinary tract in minor complaints, and for minor joint pain. Root: lower urinary tract symptoms related to benign enlargement of the prostate.
Saw palmetto
Relief of lower urinary tract symptoms related to benign prostatic hyperplasia, after a doctor has excluded serious conditions.
Cranberry
Reducing the chance of repeat urinary tract infections in some groups — not treating an infection that is already present.
Devil's claw
Relief of minor joint pain, and of mild digestive complaints such as bloating and loss of appetite.
Feverfew
Prophylaxis of migraine headaches, after serious conditions have been excluded by a doctor.
Keep the whole list in one place
TempoLife logs supplements alongside food, sleep and how you actually felt — so the answer to "what are you taking?" is a screen, not a guess.