IngredientsBlue cohosh (Caulophyllum thalictroides) is a species of flowering plant in the Berberidaceae (barberry) family. It is also known historically under the common names "papoose root" and "squaw root," though these latter terms are now considered culturally insensitive. The common name "cohosh" is probably derived from an Algonquian word meaning "rough." The genus name comes from the Greek words kaulos, meaning "a stem," and phyllon, meaning "a leaf." The species name recognizes that the foliage is similar to meadow rue (Thalictrum).
Caulophyllum thalictroides, commonly called blue cohosh, is a herbaceous perennial native to rich, mesic forests, wooded bluffs, slopes, and ravines in much of the northern and eastern United States. It is a member of the Berberidaceae family and a long-lived herbaceous perennial that is native to the moist woodlands of the upper Appalachian Mountain Range. It grows in mesophytic forest environments ranging from southern Canada (Manitoba to the Maritimes) southward to Arkansas, Alabama, and Georgia.
Spreading and bushy when mature, blue cohosh is a large, many-stemmed perennial, 1–3 feet tall. Ternately compound leaves appear at mid-stem, emerging a smoky blue in spring and turning bluish-green at maturity, and young plants are covered with a whitish, waxy bloom. Flowers give way in summer to attractive berry-like seeds that mature from green to blue, which resemble small grapes and provide good ornamental interest into fall after foliage decline.
Blue cohosh requires moist soils and deep shade, meaning logging in forestlands is a threat to its populations. Overharvesting is also a threat, as blue cohosh seeds may take up to three seasons to germinate. Caulophyllum thalictroides is listed as "Threatened" in the state of Rhode Island.
Dietary supplements containing dried roots or extracts of the roots and/or rhizomes of blue cohosh (Caulophyllum thalictroides) are widely available. Blue cohosh is available as dried root, capsules, and in tinctures (liquid extracts). Traditional forms also include decoctions and teas. Blue cohosh should not be confused with the far more popular black cohosh — these two plants are not botanically similar and yield very different medicinal properties.
Blue cohosh holds a significant place in the traditional medicine of numerous Indigenous peoples throughout eastern North America, with documented use by the Ojibwe, Menominee, Potawatomi, Cherokee, and many other nations. Indigenous midwives and herbalists used preparations from the roots and rhizomes for various reproductive health purposes, earning it great respect as a powerful medicinal plant.
Blue cohosh was used by Menomini, Meskawi, Ojibwe, and Potawatomi tribes for menstrual cramps, suppression of profuse menstruation, and induction of contractions in labor. According to a medical botany text published in 1847, Native American women would drink a tea made from the root in the weeks before childbirth to prepare their bodies for delivery. The roots were widely used by Native Americans as an herbal medicine to treat a range of ailments and as a general tonic.
The plant's medicinal use was adopted by early European settlers, and blue cohosh became an important component of 19th-century American folk medicine and the emerging field of "eclectic" herbal medicine. It was officially recognized in the United States Pharmacopoeia from 1882 to 1905 and continued to be used by herbalists, midwives, and some physicians well into the 20th century. Blue cohosh was used for labor induction, amenorrhea, dysmenorrhea, menorrhagia, and the induction of abortion, and was also listed in the National Formulary from 1916 to 1950.
It was a major ingredient in the popular Eclectic preparation "Mother's Cordial," which also included Mitchella repens, Rubus idaeus, Cimicifuga racemosa, and Chamaelirium luteum. Blue cohosh is one of the oldest indigenous American plant drugs and was introduced to the medical field in 1813 by Peter Smith, an Indian herb doctor.
In the 19th-century Eclectic Medicine movement, blue cohosh was regarded as an emmenagogue, parturient, and antispasmodic. The British Herbal Pharmacopoeia listed it in 1983 as both a spasmolytic (muscle relaxant) and an emmenagogue. Traditional applications included absent periods, painful periods, heavy bleeding, pelvic congestion, and even early-term abortion. It was also described as a general uterine and ovarian tonic.
The traditional indigenous use of blue cohosh was in much lower dosages and for stalled labor rather than as a general labor aid. It was also traditionally prepared as a decoction rather than a tincture, which may change the availability of certain compounds to unsafe quantities, as the decoction extracts a lower quantity of alkaloids.
The primary constituents of blue cohosh are its alkaloids and saponins. The structures of the alkaloids magnoflorine, baptifoline, anagyrine, and N-methylcytisine have been known for many years. Additional alkaloids identified from the rhizomes include the novel alkaloid thalictroidine, as well as taspine, magnoflorine, anagyrine, baptifoline, 5,6-dehydro-α-isolupanine, α-isolupanine, lupanine, N-methylcytisine, and sparteine.
The alkaloids magnoflorine, baptifoline, anagyrine, and N-methylcytisine, as well as certain saponins, are constituents with toxicological relevance.
The saponin element was deduced to contain the substances caulosaponin (C51H88O17·4H2O) and caulophyllosaponin (C66H104O17). The last ten years have seen a great increase in the isolation and identification of the large number of saponins present in blue cohosh. Identified compounds include caulophyllogenin and hederagenin arabinopyranosides, caulophyllines and caulophyllumines, lupanine, sparteine, taspine, and cauloside, among others.
The root also contains essential fatty acids, glucosides, phytosterols, saponins, and resinous essential oil. Blue cohosh's saponins, particularly caulosaponin, are derived from the triterpenoid saponin hederagenin. These substances are considered to be phytoestrogens because of their steroid backbone.
The roots and rhizomes of Caulophyllum thalictroides, traditionally used as an aid for childbirth, contain several active alkaloids and saponins which act directly on uterine smooth muscle resulting in an oxytocic response. The two glycosides caulosaponin and caulophyllosaponin are thought to activate smooth muscle contractions and specifically stimulate uterine contractions.
N-methylcytisine is understood to be the agent responsible for the oxytocic effect, increasing the regularity and strength of uterine contractions by directly binding to nicotinic cholinergic receptors on the smooth muscle. Early experimental work concluded that blue cohosh was the only drug tested that increased the rate and amplitude of uterine muscle contraction; this was further substantiated when Ferguson and Edwards (1954) injected anesthetized albino rats with varying amounts of the isolated crystalline glycoside and demonstrated increase in uterine tone, contraction rate, and duration of contraction.
Blue cohosh contains the plant alkaloid N-methylcytisine, which is a nicotinic acetylcholine receptor agonist. Methylcytisine has a nicotinic-like action resulting in blood pressure increases, respiratory stimulation, and increased intestinal motility.
Smooth muscle stimulation has been seen in vitro on small intestine and in vivo on coronary blood vessels of small animals using caulosaponin. Caulosaponin has also demonstrated an oxytocic effect on tissue from rat uteri, in vitro constriction of carotid vessels, myocardial toxicity, and intestinal spasmogenicity on isolated intestinal tissue.
In vitro research investigated the effects of blue cohosh components on the suppressive expression of iNOS and proinflammatory cytokines after the activation of microglia with lipopolysaccharide (LPS). The expression of iNOS, TNF-α, IL-1β, and IL-6 was determined by western blotting and gene expression. Blue cohosh treatment suppressed the elevation of LPS-induced iNOS expression in a concentration-dependent manner in microglia cells. Blue cohosh constituents also suppressed the expression of TNF-α, IL-1β, and IL-6. In addition, blue cohosh extract suppressed the expression of COX-2, iNOS, and proinflammatory cytokines in adrenal glands of mice. These results demonstrate that constituents of blue cohosh exert anti-inflammatory effects through the inhibition of expression of iNOS and proinflammatory cytokines.
The C. thalictroides methanol extract and three saponins — cauloside A, saponin PE, and cauloside C — exhibited concentration- and time-dependent mitochondriotoxic activities. Upon treatment, cell respiration rate rapidly increased and then dramatically decreased within minutes. Mechanistic studies revealed that C. thalictroides constituents impair mitochondrial function by disrupting membrane integrity. These studies provide a potential etiological link between this mitochondria-sensitive form of cytotoxicity and idiosyncratic organ damage.
Overall evidence level: No high-quality clinical trials exist; animal and in vitro data only, with documented human adverse events.
There are no high-quality clinical trials regarding the use of blue cohosh for cervical ripening or induction of labor. A trial conducted in 1999 reported equivocal results for homeopathic use of caulophyllum D4 versus placebo as an intervention to induce labor following premature rupture of membranes (N=40). A 2005 Cochrane review found insufficient evidence to support the use of homeopathic caulophyllum for cervical ripening or induction of labor.
According to a survey of midwives in the United States, approximately 64% of midwives reported using blue cohosh as a labour-inducing aid. It was typically given as a tincture: 5 drops every 4 hours or 10 drops in hot water every 2 hours. Seventy-five percent of midwives who used herbal preparations gave them before or instead of the synthetic hormone Pitocin. Sixty-nine percent of midwives who used herbal preparations learned about them from other midwives, and only 4% cited formal research publications.
In studies of rats, extracts of Caulophyllum demonstrated inhibition of ovulation and effects on the uterus. However, uterine stimulant properties observed using blue cohosh extract on isolated guinea pig tissue were not replicated in subsequent in vivo studies with cats, dogs, and rabbits, which failed to demonstrate uterine activity.
Despite widespread knowledge and use of blue cohosh, there are no clinical trials on which to base dosing recommendations, and concerns regarding toxicity outweigh potential therapeutic benefit.
Overall evidence level: Traditional use only; no controlled clinical trials identified.
In the 19th-century Eclectic Medicine movement, blue cohosh was regarded as an emmenagogue, parturient, and antispasmodic. It continues to be used for regulating the menstrual cycle and inducing uterine contractions. There are no identified clinical human studies specifically investigating blue cohosh for dysmenorrhea, amenorrhea, or menorrhagia as primary endpoints. Evidence for these uses remains entirely in the domain of traditional and historical accounts.
Overall evidence level: Preclinical (in vitro and animal data only); no human clinical trials.
Blue cohosh was commonly used as traditional medicine for the treatment of menopausal symptoms, rheumatic pain, and as an anti-inflammatory remedy. In particular, extract of blue cohosh roots has been used as an anti-inflammatory antipyretic in traditional medicines.
Suppression of proinflammatory cytokines and other mediators of inflammation has been demonstrated in vitro with blue cohosh saponins. These results demonstrate that constituents of blue cohosh exert anti-inflammatory effects through the inhibition of expression of iNOS and proinflammatory cytokines, and therefore blue cohosh may have therapeutic potential for the treatment of inflammation-related diseases. These findings are preliminary and have not been validated in human clinical trials.
Overall evidence level: Evidence insufficient; one small equivocal trial.
The homeopathic remedy made from blue cohosh is called Caulophyllum, and is recommended for menstrual cramps, PMS, dysmenorrhea, and support during childbirth. Homeopaths may also prescribe Caulophyllum for gout, rheumatism, false labor pains, and gonorrhea. The only clinical trial in this area — assessing homeopathic Caulophyllum D4 for induction of labor — was small (N=40) and produced equivocal results.
Blue cohosh's antispasmodic properties have led to its use in some cases of asthma, colic, and nervous coughs. Blue cohosh is also used to reduce pain in some cases of rheumatoid arthritis. However, there is no credible clinical evidence that blue cohosh is effective for any of the conditions for which it has been used.
Blue cohosh is available as dried root, capsules, and in tinctures (liquid extracts). Because no high-quality clinical trials have established safe or effective dosing in humans, the following figures reflect only what has been reported in the literature and surveys:
There are no clinical trials on which to base dosing recommendations, and concerns regarding toxicity outweigh potential therapeutic benefit. The appropriate dose of blue cohosh depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for blue cohosh.
A newborn infant whose mother ingested blue cohosh to promote uterine contractions presented with acute myocardial infarction associated with profound congestive heart failure and shock. The infant remained critically ill for several weeks, although he eventually recovered. Other causes of myocardial infarction were carefully excluded. Blue cohosh contains vasoactive glycosides and an alkaloid known to produce toxic effects on the myocardium of laboratory animals. This was described as the first case of deleterious human fetal effects from maternal consumption of blue cohosh.
There are three case reports in the scientific literature that blue cohosh taken at the time of delivery may cause: (1) perinatal stroke, (2) acute myocardial infarction, profound congestive heart failure and shock, and (3) severe multi-organ hypoxic injury. Blue cohosh may cause adverse effects such as high blood pressure, high blood sugar, and chest pain. The use of blue cohosh to induce labor has been associated with life-threatening complications in the infant, including seizures.
A 21-year-old female developed tachycardia, diaphoresis, abdominal pain, vomiting, and muscle weakness and fasciculations after using blue cohosh in an attempt to induce an abortion. These symptoms are consistent with nicotinic toxicity and probably resulted from methylcytisine known to be present in blue cohosh. The patient's symptoms resolved over 24 hours and she was discharged.
Blue cohosh methanol extract exhibited mitochondriotoxic activity. Used by some U.S. midwives to help induce labor, blue cohosh has been associated with perinatal stroke, acute myocardial infarction, congestive heart failure, multiple organ injury, and neonatal shock. Some of the compounds found in blue cohosh, such as caulophyllum saponin, methylcytisine, and caulosaponin, appear to constrict coronary vessels, limiting blood flow to the heart and reducing its ability to pump.
There is in vitro evidence that blue cohosh may have teratogenic, embryotoxic, and oxytocic effects. The nicotinic alkaloid N-methylcytisine, a potent toxicant, has been found in all dietary supplements of blue cohosh analyzed. The teratogenic alkaloid anagyrine has been found in some but not all dietary supplements. Other blue cohosh constituents are known to interfere with the ability of a newly fertilized ovum to implant in the uterus, damage the uterus and thyroid, and cause severe birth defects in cattle and laboratory rats.
Blue cohosh root contains N-methylcytosine, which has nicotine-like effects, and caulosaponin, a glycoside that constricts coronary vessels and may have oxytocic activity. It has been used to promote labor. No data exist on the safety and efficacy of blue cohosh in nursing mothers or infants; however, it can cause severe gastrointestinal and cardiovascular toxicity, including in neonates whose mothers used it to stimulate labor. In lactation, the safety of blue cohosh is unknown.
Canadian regulations require that any products containing this herb be labeled as not for use in pregnancy.
Touching blue cohosh can cause skin irritation, and many parts of the plant are toxic if eaten in large amounts, leading to nausea and diarrhea. The berries, roots, and leaves of this plant may cause skin irritation if touched. The berries are also poisonous. When used in high doses as an abortifacient, symptoms similar to nicotine poisoning can occur, including nausea and emesis, headache, dizziness, muscle fasciculations, tachycardia, tachypnea, hypertension, seizure, and respiratory failure.
There is concern that blue cohosh may interact with antidiabetic drugs — by increasing glucose levels; with antihypertensive drugs — by increasing blood pressure; and with nicotine, by increasing its effects. These interactions are based on known mechanisms of the plant's alkaloid constituents rather than dedicated pharmacokinetic studies, and no formal human drug-interaction studies have been published.
There is no credible evidence that blue cohosh is effective for any of the conditions for which it has been used. Furthermore, several published reports cite cases of serious side effects to infants caused by blue cohosh. There is an increasing awareness of the dangers of blue cohosh even within the traditional and alternative medicine community as research and case studies have highlighted its potential dangers.
Given these reports, the availability of safe alternatives for stimulating labor, and the lack of studies to document the herb's efficacy and safety, experts strongly advise against using blue cohosh.
Black cohosh and blue cohosh (Caulophyllum thalictroides) are different herbs, and the NIH's National Center for Complementary and Integrative Health (NCCIH) specifically distinguishes them, noting the serious safety concerns associated with blue cohosh that are not shared with black cohosh.
Health conditions that Blue cohosh may help support.
Body systems that Blue cohosh may help support.
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