Black Cohosh. (Actaea racemosa, Cimicifuga racemosa) This herb has received quite a bit of scientific attention for its possible effects on hot flashes. Studies of its effectiveness in reducing hot flashes have produced mixed results. However, some women report that it has helped them. Recent research suggests that black cohosh does not act like estrogen, as once thought. This reduces concerns about its effect on hormone-sensitive tissue (eg, uterus, breast).