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Black Cohosh Side Effects: Actea racemosa, Cimifuga foetida, and the Naranjo Scale

Black cohosh side effects is a complicated subject.  As someone who studied herbal medicine, with a bachelor's degree in business communications, I have a different perspective than most.  

First, let's identify the issues:  we need to understand a bit about the problem of adulteration in the herbal products industry, the actual side effects from taking black cohosh, and the reporting and analysis of cases of black cohosh causing liver damage.

What do We Mean When We Say "Black Cohosh?"

Many website authors begin writing about the subject of black cohosh by stating that this plant was used by Native Americans for many years to treat female complaints.  While this is true, these same authors go on to talk about many different substances, while still referring to them as black cohosh.  

So, what are we really talking about?  The plant the Native Americans used has the botanical name Actea racemosa.  This exact plant used to have a different botanical name, Cimicifuga racemosa.  These two names refer to the same plant. 

 Any other plant that starts with Actea or Cimicifuga, but has a different name after it than racemosa, is a different plant.  Not the one the Native Americans and other women have used for generations for female complaints.  Not the one that will help with hot flashes and other menopausal symptoms.  Not the one you want to be using.  And as a side note, standardized black cohosh products are also not the same as the substance that Native Americans were using.

We are especially looking out for the Asian species, one of which is called Cimicifuga foetida.  These plants are not intended to be used for hot flashes or other menopausal symptoms.

Black Cohosh Side Effects:  Adulteration

That brings us to the state of the industry.  Herbal supplements are regulated, but not the same way drugs are. This means it is much easier for a supplier to sell a different variety of plant without saying so, or mix in a cheaper plant with the real plant, which could lead to black cohosh side effects.  Like putting in a different variety of Actea, but still calling it black cohosh.  

This may be accurate, but it is misleading to the consumer.  According to Maturitas (2012), a European menopause journal, one study found that many American black cohosh products contain plant varieties other than Actea racemosa.  

You MUST get in the habit of reading labels.  I never buy any herbal or nutritional supplement without reading the ingredient label.  

If a website is selling a product and does not publish it's ingredient list, I don't buy it.  Period.  And you shouldn't either.  

If the ingredient list says black cohosh, this is insufficient data for you to know which product or products are really in the bottle.

Labeling is one thing, adulteration is another.  I only buy herbal supplements from three or four companies. Herb Pharm and Oregon's Wild Harvest are my preferred brands.  This is because they are highly reputable companies committed to the ethical harvesting, manufacturing and distribution of the plants.  

Oregon's Wild Harvest actually has a guarantee of ingredient identity.  From their website,  “We verify the ingredient identity using infrared spectroscopy and checking the color, taste, and smell, requiring a match against our specifications and our database. This allows us to guarantee that the identification meets a consistent set of standards every time.”

Just in case you think this isn't a serious issue, consider this statement by Roy Upton, herbalist (HerbalGram, 2011), “With GMPs [good manufacturing practices] in full force there are now a lot of companies realizing that the supply chain for ingredients that pass identity and quality good manufacturing practice requirements has shrunk dramatically. Ingredients that used to readily pass manufacturer specifications are now failing when proper identity and quality tests are applied.” 

Black Cohosh Side Effects:  Actea racemosa

Black cohosh side effects are usually mild and uncommon.  In excess amounts or with people especially sensitive to the herb they include: frontal headaches, flushed face, dizziness, nausea and visual disturbance.  

Compare that to, say, adverse reactions from Premarin (taken from Physician's Drug Handbook, 5th Edition): headache, dizziness, chorea, depression, libido changes, lethargy, thrombophlebitis, thromboembolism, hypertension, edema, increased risk of stroke, pulmonary embolism, myocardial infarction, melasma, urticaria, acne, sebarrhea, oily skin, hirsutism or hair loss, worsening of myopia or astigmatism, intolerance to contact lenses, nausea, vomiting, abdominal cramps, bloating, diarrhea, constipation, anorexia, increased appetite, weight changes, breakthrough bleeding, altered menstrual flow, dysmenorrhea, amenorrhea, cervical erosion, altered cervical secretions, enlargement of uterine fibromas, vaginal candidiasis, cholestatic jaundice, hyperglycemia, hypercalcemia, folic acid deficiency, breast changes (tenderness, enlargement, secretions), leg cramps

Black Cohosh Side Effects: Precautions:

Avoid this herb if you have or have had breast cancer or other reproductive organ cancers.  Do not use in pregnancy. If you have low blood pressure, this herb may lower it even more. Do not confuse it with Blue Cohosh (Caulophylum t., an entirely different herb).  Do not take black cohosh if you are taking estrogen.  

Black Cohosh and Your Liver: Is Black Cohosh Liver-toxic or Not?

Many websites include statements about black cohosh side effects that are about cases of the plant being associated with liver toxicity.  These sites generally go on to say that we still don't know whether or not black cohosh is hepatotoxic.  

In my recent research, it seems that black cohosh has been found to be safe.  Of course, it never hurts to be cautious, and if you have any concerns about this, you should have your doctor test your liver enzymes from time to time.  Here are some articles that have reviewed and/or analyzed black cohosh studies and reports.

Teschke, Bahre, Genthner, Fuchs, Schmidt-Taenzer, & Wolff (2009) analyzed and reviewed data for 69 reported cases of black cohosh and liver toxicity.  They state in the article that these are “all 69 reported cases.”  Their conclusion: “The analysis of 69 cases shows little, if any, supportive evidence for a significant hepatotoxic risk of BC.”

In an American article, Norton (2011) reports, in “the new study, reported in the journal Menopause, researchers combined the results of five previously published clinical trials of the black cohosh product Remifemin. Together, the studies involved more than 1,100 women who used either this black cohosh product or a comparison substance -- either an inactive placebo or a hormonal medication called tibolone -- for three to six months...there was no evidence that black cohosh triggered harmful changes in liver enzymes...an expert not involved in the study said the findings are consistent with other evidence that black cohosh is safe for the liver.”

In another study, noted in the same article, “Dr. Richard B. van Breemen, a professor at the University of Illinois College of Pharmacy in Chicago...over one year, there was also no evidence that the herb harmed women's liver function...van Breemen told Reuters Health in an email, 'In particular, we tested for liver damage in our study and found that black cohosh was not hepatotoxic (toxic to the liver).'”

Black Cohosh Side Effects: An Evaluation of Methods Assessing Causality

I just discovered this myself:  it turns out there are different standards for assessing a causal relationship between ingestion of a substance, such as black cohosh, and liver toxicity (hepatotoxicity).  

Teschke, Schmidt-Taenzer, & Wolff (2011) evaluated two methods of assessing causality with organ toxicity, and found that a liver-specific method (Council for Organizations of International Medical Sciences, or CIOMS) was preferable to a non-liver-specific method (the Naranjo scale) for determining hepatotoxicity causal relationships.

For information about using black cohosh for hot flashes, including dose information, see black cohosh for hot flashes


News About Black Cohosh. (2012). Maturitas, 71, 92-93.  Retrieved from ScienceDirect.

Nonprofit collaboration addresses adulteration of botanical dietary ingredients.  HerbalGram. Retrieved February 22, 2012 from http://cms.herbalgram.org/press/2011/Nonprofit_Collaboration_Addresses_Adulteration_of_Botanical_Dietary_Ingredients.html 

Norton, A. (2011).  Study finds no evidence black cohosh damages liver.  Reuters.  Retrieved February 21, 2012 from http://www.reuters.com/article/2011/01/28/us-black-cohosh-idUSTRE70R7IL20110128

Teschke, R., Bahre, R., Genthner, A., Fuchs, J., Schmidt-Taenzer, W., & Wolff, A.  (2009).  Suspected black cohosh hepatotoxicity-challenges and pitfalls of causality assessment.  Maturitas, 2009 Aug 20;63(4):302-14.  Retrieved from PubMed.

Teschke, R., Schmidt-Taenzer, W., & Wolff, A. (2011).  Spontaneous reports of assumed hepatotoxicity by black cohosh: is the liver-unspecific Naranjo scale precise enough to ascertain causality?  Retrieved February 22, 2012 from http://www.ncbi.nlm.nih.gov/pubmed/21702069