Native Americans used this herb to reduce menstrual pain and stimulate menstruation in women suffering from amenorrhea (the absence or discontinuation of normal menstrual cycles). This herb was also commonly used to induce labor and relieve the pain of childbirth, as indicated by its common names "squaw root" or "papoose root." Research indicates that the glycoside caulosaponin may be responsible for this herb's uterine stimulant properties. In addition, Native Americans boiled the root of this herb to make a drink to promote sweating and relieve fever. What is this herb?