Emmenagogues are herbs which stimulate blood flow in the pelvic area and uterus; some stimulate menstruation. Women have used plants such as mugwort, parsley, chamomile and ginger to cause an abortion or prevent pregnancy (see Abortifacient). Others use emmenagogues to stimulate menstrual flow when menstruation is absent for reasons other than pregnancy, such as hormonal disorders or conditions like oligomenorrhea (infrequent or light menses).