Black cohosh does not appear to have estrogenic properties as tested in a variety of lab testing (in vitro studies), animal studies or human studies . In the past it was mistakenly referred to as phytoestrogen  which it is not. There were some concerns about toxicity to the liver, but in a study with 400 menopausal women where they used black cohosh at 20mg tablets for 12 months,  there was no effect on the uterus or liver. If one makes a decision to use this herb, I would suggest to work closely with the primary physician, that would also help in the selection of the right brand and dosage.

Moshe Frenkel, M.D.