The American Herbal Pharmacopoeia (AHP) announced in June the publication of a new monograph and therapeutic compendium for blue cohosh (Caulophyllum thalictroides, Berberidaceae) root and rhizome.¹ AHP monographs provide standards for determining herb purity and authenticity, as well as information on quality control issues. The therapeutic compendium — which, depending on the herb in question, can be used by companies to help substantiate product safety claims — offers a comprehensive review of available pharmacological data on the plant and includes information on dosage, side effects, toxicology, and drug interactions, as well as guidance on the development of structure-function claims.

Reports of toxicity associated with blue cohosh, combined with its continued popularity as a natural birthing aid, prompted AHP to publish the monograph — its 33rd. “Blue cohosh has been implicated in a few cases of toxicity that include neonatal cardiac toxicity and maternal toxicity,” said AHP Executive Director Roy Upton (email, July 18, 2012). “Because blue cohosh was the primary herb used in birthing practices of herbalists, integrated medical doctors, and midwives for more than 100 years, we felt it was important to address this concern.”

Aviva Romm, MD, a co-author of AHP’s latest monograph, began research on blue cohosh as a medical student at Yale. “I wanted … to explore whether in fact risk outweighed the benefits of use so that midwives could be appropriately informed, or whether a case for relative safety could be established so that those who chose to use it could do so in the most informed, evidence-based manner,” she said (email, July 18, 2012).

Blue cohosh is unrelated to the similarly named black cohosh (Actaea racemosa, Ranunculaceae), for which an AHP monograph is also available. “However, these are taxonomically unrelated plants that are not typically confused,” wrote Upton and Dr. Romm in the monograph.¹ “According to Lloyd and Lloyd (1931), ‘cohosh’ is an Algonquin word meaning ‘it is rough’ (with hairs) and was originally applied to the bristly fruit of Ribes lacustre [Grossulariaceae; also known as prickly black currant or bristly black gooseberry],” explained Upton.

Traditionally, blue cohosh has been used as a diaphoretic (sweat inducer), diuretic, expectorant, and for arthritis, but it is used most commonly in pregnancy and gynecology, most specifically as a way to avoid conventional methods of induction, which contribute to the high rate of premature births in the United States. According to Upton, “the safety of blue cohosh has to also be considered in this context.” Case reports of adverse events in recent years, however, have called for an evaluation of the plant’s pharmacological and safety data, which AHP believes it has provided.

A review of the data suggests that blue cohosh is indeed associated with certain adverse events reported, but confounding factors make it impossible to establish a causal relationship. “What I walked away with most from this monograph is the need to use the herb within the context of those most experienced with it and in the context of how it was most widely used traditionally, in combination with other botanicals,” said Upton.

The monograph notes that Eclectic physicians in the latter part of the 19th and early part of the 20th centuries almost always used the herb in combination formulas, “which inherently limits the exposure to potentially toxic substances,” Upton added. “It may still prove to be a safe and effective induction agent when used by highly trained and experienced birthing professionals, but concern regarding potential toxicity has limited its use in birthing.”

The blue cohosh root and rhizome monograph is available through AHP’s website, www.herbal-ahp.org. A PDF version of the publication is available for $35.95, and a hard copy can be purchased for $44.95.

—Tyler Smith

Reference

1. Romm A, Upton R (eds.). Blue Cohosh Root and Rhizome. American Herbal Pharmacopoeia website. Available at: www.herbal-ahp.org/. Accessed July 20, 2012.