Black cohosh hepatotoxicity: quantitative causality evaluation in nine suspected cases.

OBJECTIVE

Black cohosh (BC), synonym for Actaea racemosa and Cimicifuga racemosa, is a herbal remedy for the treatment of menopausal symptoms. Recently, worldwide discussions have emerged as to whether its use maybe associated with the risk of rare hepatotoxicity in a few susceptible women.

METHODS

We have evaluated the causal relationship in nine cases with suspected hepatotoxicity by the use of BC. The updated Council for International Organizations of Medical Sciences scale was used to quantitatively assess the causality for BC.

RESULTS

In eight of nine patients with liver disease, causality for BC +/- comedication was excluded (n = 4) or unlikely (n = 4). The failure to ascribe causality in these cases was mainly due to alternative diagnosis, missing temporal association and dechallenge, and presentation of low quality data. In only one case, causality was possible for a BC preparation of an unknown brand taken for 2 months with an unknown daily dose. Confounding factors in this case include symptomatic cholelithiasis and fatty liver. Comedication with synthetic drugs and herbal or other dietary supplements was reported in five of nine patients.

CONCLUSIONS

In nine cases of patients with liver disease, causality for BC +/- comedication was possible (n = 1), unlikely (n = 4), or excluded (n = 4). Due to this lack of significant circumstantial evidence, the present study shows little, if any, hepatotoxic risks by the use of BC in the analyzed cases.