Emmenagogues are substances or herbs which stimulate blood flow in the pelvic area and uterus, and have the ability to stimulate menstruation. They can work in a variety of ways, but the end result is menstruation. Women have used plants such as mugwort, parsley and ginger to prevent or terminate early pregnancy. 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). The most commonly-used, mild strength emmenagogues are: yarrow, feverfew, rosemary and sage, and medium strength ones include parsley, Queen Anne’s lace seeds and black cohosh.