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Limited evidenceWomen's health

Blue Cohosh

A North American root used traditionally to induce labour and ease menstrual cramps. There is no controlled clinical evidence that it works, and there are documented cases of severe harm to newborns after maternal use, which makes this one of the few herbs we would actively advise against.

What the science says

  • No controlled evidence for labour induction or cramps Limited evidence

    PubMed contains no randomized or controlled trial of blue cohosh for labour induction, cervical ripening or dysmenorrhoea. Use rests on traditional midwifery practice alone.

  • Documented serious neonatal harm Limited evidence

    A case report in J Pediatr described profound neonatal congestive heart failure attributed to maternal consumption of blue cohosh near term. Case reports are individually weak evidence, but for a plant containing cardiotoxic and nicotinic alkaloids this is a signal that should not be dismissed.

Dosage & safety

Studied doseNo dose can be recommended. We do not consider this herb suitable for self-administration at any dose.
SafetyContains caulosaponin and N-methylcytisine, which have cardiotoxic and nicotine-like activity. Reported harms include neonatal heart failure, stroke and seizures after maternal use, plus maternal nausea, headache and raised blood pressure. Absolutely avoid in pregnancy and while trying to conceive, and avoid in anyone with cardiac disease, hypertension or glaucoma. Labour induction is a medical procedure and belongs in a supervised setting.

How to take it

TimingNot applicable — we do not consider blue cohosh suitable for self-administration at any dose.
With food?Not applicable, and food does not reduce the cardiac risk.
Worth knowingIf you are looking for something to start labour, that decision belongs with a midwife or obstetrician — the reported harms here include neonatal heart failure and stroke.

Interactions

With medications

  • blood pressure and cardiac medication

    Blue cohosh glycosides have cardiotoxic and nicotine-like activity that can raise blood pressure and disturb heart rhythm, working against treatment. Do not use it at all if you take these drugs

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does blue cohosh induce labor?

There is no controlled trial of blue cohosh for labour induction, cervical ripening or menstrual cramps, and severe harm to newborns has been documented after maternal use. We actively advise against it; labour induction belongs in a supervised medical setting.

Is blue cohosh safe during pregnancy?

No. Blue cohosh contains cardiotoxic and nicotine-like alkaloids, and reported harms after maternal use include neonatal heart failure, stroke and seizures. Absolutely avoid it in pregnancy and while trying to conceive.

What is a safe dose of blue cohosh?

No dose of blue cohosh can be recommended; we do not consider it suitable for self-administration at any dose. Avoid it entirely if you have heart disease, hypertension or glaucoma, or take cardiac medication.

Scientific references

Related in Women's health

Herbal medicines: what the evidence says (335)