Women of all ages have historically used emmenogogues--herbs that stimulate menstrual flow--to regulate the menstrual cycle. Herbal emmenogogues can act as emergency contraceptives or as treatments for oligomenorrhea (light, infrequent menstruation). Some women may also induce menstruation early to prevent a period from coinciding with an inconvenient event, such as a vacation or holiday. If you are interested in making your menstrual cycle come early, understand that most herbal emmenogogues have not received thorough evaluation by modern scientific inquiry. Herbs that stimulate menstruation can have side effects ranging from troublesome to life-threatening. Consult your health care provider before using any herb to induce your period.
A North American medicinal herb, black cohosh has historically been used to treat almost all disorders of the female reproductive system. The National Center for Complementary and Alternative Medicine notes black cohosh's use as a traditional remedy for disorders ranging from infertility to hot flashes. Black cohosh reliably induces menstruation; however, it is also an anticoagulant, so it may cause a prolonged or heavy period.
Drugs.com identifies juniper as a known emmenogogue. While few recent studies have investigated juniper's overall effect on the body, a traditional dose may range between 2 to 10 grams of dried juniper berry.
According to the U.S. National Institutes of Health, pennyroyal is used in folk medicine as a menstrual stimulant and abortifacient. However, this toxic member of the mint family causes serious side effects. Case reports link pennyroyal to nausea, vomiting, diarrhea, psychosis, multiple organ failure, coma and death.
Tansy flower contains large quantities of the menstrual stimulant thujone. While tansy effectively induces menstruation, it does so only at toxic or near-toxic doses. Drugs.com notes that tansy is no longer used in herbal medicine; its risks far outweigh its possible benefits. Tansy can cause heart palpitations, severe gastrointestinal problems, convulsions, coma and death.
A gentle menstrual stimulant, parsley may help to induce a menstrual cycle with fewer side effects than stronger herbs. Parsley is relatively weak as an emmenogogue when taken internally. Some herbalists recommend using parsley as a pessary (vaginal suppository) to stimulate menstrual flow.