As with any medication or supplement, side effects are possible with
black cohosh (
Actaea racemosa, Cimicifuga racemosa). People often assume that natural products are always free of side effects, especially dangerous side effects. However, this is simply not the case.
(This article covers many, but not all, of the possible side effects of black cohosh. Your healthcare provider can discuss a more complete list of black cohosh side effects with you.)
Possible Side Effects of Black Cohosh
Possible bothersome (although not usually serious) black cohosh side effects may include:
- An upset stomach
- Headaches
- Breast tenderness
- Dizziness
- Weight gain
- A heavy feeling in the legs.
There are a number of potential side effects with black cohosh that you should report to your healthcare provider. These include, but are not limited to:
- Signs of liver damage, such as upper right abdominal pain (stomach pain), yellowing of the whites of the eyes or skin (jaundice), dark urine, or high liver enzymes (found using a blood test)
- Unexplained vaginal bleeding or spotting
- Signs of an allergic reaction, such as a rash, hives, itching, swelling of the mouth or throat, wheezing, or difficulty breathing.
Unpredictable side effects may also occur due to possible contaminants in black cohosh products. Because herbs and supplements are not as tightly regulated as prescription or non-prescription drugs, they are sometimes contaminated with other herbs, medications, or even heavy metals. In order to avoid such problems, it is important to choose black cohosh products that are made by trustworthy manufacturers. Your pharmacist can help you choose a good black cohosh product.
Serious problems have been reported in newborns whose mothers took black cohosh (in combination with blue cohosh) to induce labor. However, it is thought that these problems were probably due to the blue cohosh, rather than the black cohosh.