Premenstrual syndrome (PMS) is a recurrent disorder that occurs in the luteal phase of the menstrual cycle. It is characterized by intense physical, psychologic, and behavioral changes that interrupt interpersonal relationships and disrupt the lives of affected women. Up to 40% of women of childbearing age have some form of PMS, and up to 10% have severe signs and symptoms. There are at least four types of PMS, each with its own constellation of signs and symptoms. Related illnesses or illnesses that need to be ruled out include diabetes mellitus, thyroid dysfunction, hypoglycemia, and primary and secondary dysmenorrhea. Difficulty in identifying the exact etiology of the disorder is documented. Diagnostic issues include confusion over exact signs and symptoms, differential diagnoses, pertinent laboratory data, careful history taking, and the importance of women recording a menstrual cycle history on a calendar. Recommended first-line treatments include a diet low in salt, fat, caffeine, and sugar; an aerobic exercise regimen; and stress reduction via changes in lifestyle.