The side effects of Black Cohosh have not been well studied and we don’t know much regarding the active substances in this herb.
Overall, Bugbane (another name for this herb) is considered very safe and well tolerated by the millions of women who use it.
It is used in Europe in its standardized form (Remifemin) since the 50s to treat the signs and symptoms of menopause.
However, Black Cohosh side effects do exist.
The side effects of Black Cohosh can depend on the preparation that is used. This means that the side effects may differ for women who use a supplement, a pill or a tincture.
As with all the herbs we are discussing, we recommend using only standardized preparations such as Remifemin to avoid getting contaminated products. This also ensures that you are getting the full dose of the advertised active compound which is not always the case with lower end products.
Some references and studies state that it is safe for up to six months. This recommendation is based only on the length of some specific studies that lasted six months. Because these studies showed no negative effects the researchers concluded that it must be safe for this period of time.
Out of this recommendation, many women draw the conclusion that it is not safe for longer use. But in reality nobody knows for sure if longer use of Black Cohosh would lead to negative effects and many women use Black Cohosh for several years.
List of Black Cohosh Side Effects
Some side effects of Black Cohosh have been reported with high doses. These side effects include:
- Nausea and Vomiting
Allergic reactions may occur in some women and include rashes, hives, itching, and swelling of lips, tongue or face. If any such symptoms occur, stop taking the herb. If the reaction is severe, seek medical help immediately.
People who are allergic to plants from the Ranunculaceae family of plants should not take Black Cohosh (Buttercup etc).
The plant contains small amounts of salicylic acid (the active ingredient in Aspirin). People with allergies to aspirin should be careful when taking this herb because it is not known how much (if any) salicylic acid commercially prepared Black Cohosh supplements contain.
The side effects of Black Cohosh for women with breast cancer are hotly debated. Women who had estrogen-sensitive breast cancer are warned to seek the advice of their health care provider before they take this herb. On the other hand, it is recommended for women who can’t take hormones to treat their menopause symptoms such as hot flashes.
Several studies were done with mice with conflicting results. Because researchers don’t know exactly about the mechanisms of the phytoestrogens on breast cancer cells, it is still uncertain how Black Cohosh will affect women with breast cancer.
Do not take Black Cohosh if you are pregnant. The herb is sometimes used to induce labor and therefore could lead to a miscarriage.
Black Cohosh and Liver Failure
here have been a few, widely publicized, reports of Hepatitis and liver failure in women who were taking this herb.
We believe that these reports are overhyped. Researchers don’t know if the women in question had a previous liver condition, or if they where taking a contaminated product, or if the culprit was really the active chemical in Black Cohosh.
There have been several instances of dangerous contaminations that were found in supplements, mostly manufactured in foreign countries without any stringent regulations. This is why we are always recommending to take only products from companies you trust.
Because of this reported Black Cohosh side effect, women who know that they have a liver illness should consult their health care provider before taking any form of this herb. If you are taking this herb and experience any form of yellowing of skin or eyes, dark urine, upper stomach pain (pain under the ribs), nausea, loss of appetite and severe tiredness, stop taking Black Cohosh and consult your physician immediately.
Drug Interactions with Black Cohosh
There are no known drug interactions.
However, if you are on hormone therapy, do not take Black Cohosh because it could increase the effects of estrogen. This herb is one of the phytoestrogens, (meaning its active compounds act like estrogen) and you could see side effects of too much estrogen. (Breast tenderness, PMS like symptoms).
Women who are taking Tamoxifen or other medications for breast cancer should talk to their doctor before taking the herb because we don’t know if the phyto estrogens in Black Cohosh interfere with the medication.
There are other Cohosh plants, such as blue cohosh or white cohosh. These are different, unrelated plants and may not be safe. Blue Cohosh’s active chemical influences blood vessels and the heart rate, and can be dangerous.
So in conclusion: There are potential side effects of Black Cohosh but the herb has an excellent safety record and helped countless women all over the world to alleviate the signs and symptoms of menopause.
If you have any concerns about Black Cohosh side effects, choose other herbs to treat your symptoms.