Black Cohosh Dangers

Actaea racemosa, also known as black cohosh, is a member of the buttercup family that is native to North America. Preparations made from the roots and rhizomes of the plant are used to treat symptoms of menopause such as hot flashes and mood swings. According to the University of Maryland Medical Center, research has produced conflicting evidence about the effectiveness and dangers of black cohosh.

Allergic Reaction

According to the American Cancer Society, people who are allergic to other members of the buttercup family should avoid black cohosh. The plant contains salicylic acid, which can cause an allergic reaction in people who are sensitive to aspirin. Allergic reactions to black cohosh are uncommon.

Liver Failure

People with liver problems or who drink excessively should not take black cohosh, warns the National Institutes of Health Office of Dietary Supplements. A few cases of liver damage have been reported with use, though there has been no research demonstrating the link between black cohosh and liver failure. The U.S. Pharmacopeia, which sets standards for drugs and supplements, advises consumers to stop taking black cohosh and contact a doctor if they experience signs of liver damage, which includes jaundice, dark urine or abdominal pain.

Side Effects

Serious side effects from black cohosh are rare, according to the American Cancer Society. When taken in large amounts, black cohosh can cause abdominal pain, headache, joint pain, dizziness, weight gain, diarrhea, slow heart rate, vomiting and tremors.

Effects on Breast Cancer Cells

There have been several clinical studies examining how black cohosh affects breast cancer cells, but the findings have been inconsistent. In a 2007 University of Pennsylvania School of Medicine study, black cohosh slowed the development of breast cancer in 949 participants with the disease. But a 2008 study by Duquesne University in Pittsburgh, reported that black cohosh caused cancerous tissue to grow in mice with tumors. This may be due to plant-based estrogens, known as phytoestrogens, found in black cohosh; however, the plant's mechanism of action is unknown. Given the lack of definitive research, the American Cancer Society advises that women should avoid taking black cohosh while they are receiving breast cancer treatment.

Drug Interactions

According to 2005 research by Yale Cancer Center, black cohosh may interfere with cancer therapy drugs such as doxorubicin, docetaxel and cisplatin. Black cohosh is also not recommended for people taking drugs to manage blood pressure, reports the American Cancer Society. Consult with a doctor about possible drug interactions before taking black cohosh.