Most women of reproductive age experience at least mild premenstrual symptoms at some point in their lives. However, around 2–10% of women have premenstrual symptoms that disrupt their daily living. This is typically diagnosed as premenstrual syndrome (PMS). Symptoms are varied and most often occur during the two weeks before a period. They can include depression, feelings of hopelessness, anger, poor concentration, headaches, bloating, breast tenderness, and irritability. Severe PMS that consistently affects daily functioning and personal relationships may be diagnosed as premenstrual dysphoric disorder (PMDD). Acupuncture may help reduce symptoms of PMS by increasing relaxation, reducing tension, and altering the brain’s mood chemistry to reduce serotonin levels and increase endorphins. It may also reduce inflammation, regulate uterine and ovarian blood flow and reduce pain.