Phase III double-blind, randomized, placebo-controlled crossover trial of black cohosh in the management of hot flashes: NCCTG Trial N01CC1.J Clin Oncol. 2006 Jun 20; 24(18):2836-41.JC
Hot flashes can cause significant morbidity in postmenopausal women undergoing or finished with breast cancer treatment. Black cohosh has been used to treat hot flashes, but definitive clinical data about efficacy have been equivocal.
A double-blind, randomized, cross-over clinical trial with two 4-week periods, was used to study the efficacy of black cohosh (1 capsule, Cimicifuga racemosa 20 mg BID) for the treatment of hot flashes in women. Participants kept a daily hot flash diary during a baseline week and then during two 4-week crossover treatment periods. Hot flash scores were measured by assigning points (1 to 4 for mild to very severe) to each hot flash based on severity and then adding the points for a given time period.
Between October 31, 2003, to March 4, 2004, 132 patients were randomly assigned. Toxicity was minimal and not different by treatment group. Patients receiving black cohosh reported a mean decrease in hot flash score of 20% (comparing the fourth treatment week to the baseline week) compared with a 27% decrease for patients on placebo (P = .53). Mean hot flash frequency was reduced 17% on black cohosh and 26% on placebo (P = .36). Patient treatment preferences were measured after completion of both treatment periods by ascertaining which treatment period, if any, the patient preferred. Thirty-four percent of patients preferred the black cohosh treatment, 38% preferred the placebo, and 28% did not prefer either treatment.
This trial failed to provide any evidence that black cohosh reduced hot flashes more than the placebo.