- Black snakeroot
- rattlesnake root
For Patients & Caregivers
There is some evidence that black cohosh is effective for menopausal symptoms. More research is needed.
It is not clear if black cohosh is beneficial for menopausal symptoms due to conflicting results from various studies. There is not enough evidence to support its anticancer effects in humans. Patients should use caution as liver failure has been reported from its use.
- Menopausal symptoms
Various studies yielded conflicting results about use of black cohosh for menopausal symptoms
- To ease painful or heavy menstruation
Clinical trials have not evaluated this use.
- Premenstrual syndrome (PMS)
There are no clinical data to support use of black cohosh for PMS.
- As a sedative
No scientific evidence supports this use.
- Hot flashes
Clinical trial results are mixed.
- You currently have, or have been treated for, an estrogen receptor-positive (ER+) cancer (It is still unclear whether black cohosh acts in the same manner as estrogen, and might therefore stimulate growth of these tumors).
- You are taking hormonal medications such as birth control pills (If black cohosh has estrogen-like activity, it will interfere with these medicines).
- Stomach upset
- Liver failure
- Hepatotoxicity (liver toxicity) has been reported following use of black cohosh.
- Two cases of liver injury resembling autoimmune hepatitis were reported after taking black cohosh. Both patients responded to treatment with corticosteroids.
- A case of coagulation activation, fluid retention, and transient autoimmune hepatitis has been reported associated with use of black cohosh.
- Bradycardia (slowing of heart beat) was observed in a woman taking black cohosh.
- Orobuccolingual dyskinesia (OBLD), involving interference with speech, tongue-biting, and eating difficulties, has been reported in a 46-year-old woman while taking a herbal supplement containing black cohosh and ginseng.
For Healthcare Professionals
Obtained from root of the plant, black cohosh is used as a dietary supplement to relieve the symptoms of menopause and dysmenorrhea. Black cohosh has antiosteoporotic effects (8) and enhances bone formation (9). Clinical studies have shown that black cohosh alone (1) (2) (3) or in combination with other herbs (4), (5) is effective in the treatment of menopausal symptoms, but data are conflicting (6) (31) (32) (36) (45). Conclusions of a meta analysis indicate insufficient evidence to support use of black cohosh for menopausal symptoms (40).
Studies evaluating black cohosh to treat hot flashes from breast cancer treatment also yielded mixed results (10) (11) (12). Further supplementation with black cohosh did not enhance bone density, improve menopausal symptoms, or 10-year risk of coronary heart disease in early postmenopausal women (37).
A black cohosh extract was shown to have antidiabetic potential in a study of mice (46). Human studies have yet to be conducted.
In vitro studies show black cohosh decreases prostate cancer cell proliferation (14) and induces an apoptotic response in liver cells (21). However, it also increased the incidence of metastatic disease in mice (16). Whether it has similar effects in breast cancer patients is not clear, although a retrospective observational study of breast cancer patients found that black cohosh enhanced disease-free survival (15).
Hepatoxicity has been associated with use of black cohosh (34), but data are conflicting (39).
Patients should consult their physicians before using black cohosh supplements.
Black cohosh relieves menopausal symptoms likely by mimicking neurostransmitters: dopaminergic, noradrenergic, serotoninergic and GABAergic effects have been demonstrated (49).
Black cohosh may have estrogenic effects, but data are conflicting (23). Studies also show that it has no effect on LH, FSH, prolactin, or estradiol (24). A black cohosh extract was shown to have antiproliferative and antiestrogenic effects in ER-negative cells. This suggests that black cohosh mediates its effects via an estrogen-independent pathway (25), possibly through HER-2 signaling (26).
Black cohosh also has been investigated for anticancer potential. In an in vitro study, it repressed the expression of cyclin D1 and ID3, and inhibited proliferation of HepG2, p53 positive, liver cells (43).
In prostate cancer cells, a black cohosh extract demonstrated antiproliferative effects, via impaired equilibrative nucleoside transporter (ENT) activity, resulting in hindered nucleoside uptake (50).
Hepatotoxicity is a major concern with black cohosh use. Evaluation of liver biopsies from two patients who took black cohosh supplements showed the pattern of pathological injury of liver cells to be identical to toxic necrosis, seen during autoimmune hepatitis (51).
- Black cohosh should not be confused with blue cohosh.
- Whether black cohosh possesses estrogenic activity is still not clear. This product should be used under the supervision of a physician.
- After reviewing 30 independent cases of reported hepatoxicity associated with black cohosh intake, the United States Pharmacopeia’s Botanical Expert Committee decided that black cohosh products should include a statement of caution concerning their use (28).
- A recent survey reported poor quality control of several black cohosh products (44).
- Gastrointestinal upset and rashes are most common followed by dizziness, headaches, nausea, and vomiting when higher than normal doses are taken (27)
- Hepatotoxicity has been reported following use of black cohosh (18) (20) (33) (34) (47).
- Two cases of liver injury resembling autoimmune hepatitis were reported after taking black cohosh. Both patients responded to treatment with corticosteroids (35).
- A case of coagulation activation, fluid retention, and transient autoimmune hepatitis has been reported associated with use of black cohosh (38).
- Bradycardia was observed in a woman following use of black cohosh (41).
- Orobuccolingual dyskinesia (OBLD), involving interference with speech, tongue-biting, and eating difficulties, has been reported in a 46-year-old woman while taking a herbal supplement containing black cohosh and ginseng (48).