Herb library · Herb · Caulophyllum thalictroides
Blue cohosh
A woodland plant of eastern North America whose root the Omaha called their "great fever medicine." Today it is best known for use near childbirth, where case reports describe serious harm to newborns; it is not the same plant as black cohosh.
Serious warning
Case reports tie blue cohosh taken near delivery to a newborn's stroke, a newborn's heart attack with heart failure, and severe organ injury, and a 21-year-old who took it to end a pregnancy developed nicotine-like poisoning. A 2008 systematic review advised that it be used only under medical supervision and not sold over the counter.
Traditional use
Native to rich forests of eastern North America. Among the Omaha, Melvin Gilmore recorded that a decoction of the root was given for fevers and was considered the strongest fever medicine they knew; its Omaha-Ponca name means "great fever medicine." In the United States it has been used to bring on labor: a survey reported in a 2008 review found that about 64% of midwives had used it for that purpose.
What studies show
- Insufficient
Starting labor: a 2008 systematic review reported no trials of whether it works. It found three case reports that blue cohosh taken around delivery was followed by a stroke in a newborn, a heart attack with heart failure and shock in a newborn, and severe multi-organ injury from lack of oxygen.
- Insufficient
Fever and other uses: no studies in people were found.
Be careful of
Cautions
- PregnancyDo not use it in pregnancy or to start labor except under a doctor's or midwife's direct care: the 2008 review advised extreme caution and found lab evidence of harm to developing embryos. Its safety while breastfeeding is unknown.
- NoteIt contains methylcytisine, a nicotine-like compound. Signs of poisoning in the reported case were a fast heartbeat, sweating, stomach pain, vomiting and muscle weakness and twitching.
- NoteDo not confuse it with black cohosh, a different plant with a different safety record.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“A decoction of the root was given for fevers. This was considered the most effectual febrifuge known to the Omaha.”
Sources
- Safety and efficacy of blue cohosh (Caulophyllum thalictroides) during pregnancy and lactation (opens in a new tab) · NIH · read September 25, 2026
- Nicotinic toxicity from tincture of blue cohosh (Caulophyllum thalictroides) used as an abortifacient (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.