I’ve been on the drug tamoxifen since recovering from breast cancer. Black cohosh helps keep the drug-induced hot flashes at bay, but my doctor says the herb could increase my risk of cancer recurrence. Is this true?

The published research on black cohosh directly contradicts your doctor’s opinion. In fact, the vast majority of medical studies on this herb indicate that it is safe and beneficial for women who have had breast cancer. Thousands of women throughout Europe and North America have successfully used standardized extracts of black cohosh for relief from hot flashes and other symptoms associated with menopause. No link has ever been found between taking the herb and the worsening or recurrence of breast cancer, which is not surprising news, considering how the herb works.

Because of its powerful ability to lessen menopausal symptoms, some researchers used to believe black cohosh contained chemical compounds with estrogen-like activity. However, several well-conducted laboratory and clinical studies thoroughly disproved this notion. In fact, test tube research has shown that black cohosh can actually inhibit the growth of breast cancer cells. In addition, taking black cohosh extract has not been found to change the body’s levels of estrogen or any other hormones.

A 2003 study of premenopausal breast cancer survivors in Caracas, Venezuela, compared the use of tamoxifen for five years with or without 12 months of black cohosh extract, and researchers found that the combination significantly reduced the frequency and severity of tamoxifen-induced hot flashes. In addition, the researchers found no evidence that the herb interfered with the beneficial effects of the drug. After considering all this, I don’t see any reason to discontinue black cohosh extract.