The Full form of PMS is Premenstrual Syndrome. PMS is a combination of physical and mood disturbances that occur in the last half of a woman’s menstrual cycle after ovulation which normally end with the onset of the menstrual flow. Physical features of the premenstrual syndrome include breast tenderness and bloating. On the other hand, psychological changes include anger and depression. Monthly chemical changes are responsible for PMS. The chemical changes may involve neurotransmitters, sex hormones, and opioid peptides. PMS can be mimicked and must be distinguished from other disorders. Menstrual diary is the most helpful diagnostic tool for PMS. Treatment of PMS includes dietary changes, exercise, emotional support from family and friends, and medications. The medications for PMS include diuretics, oral contraceptives, pain killers, drugs that suppress ovarian function and antidepressants. About 90% of women experience premenstrual symptoms at some point in their lifetime. The true incidence of PMS has often been overestimated by including all women who experience any physical or emotional symptoms prior to menstruation. It is estimated that clinically significant PMS (which is moderate to severe in intensity and affects a woman’s functioning) occurs in 20% to 30% of women. It is generally most severe in women in their 4th decade of life.