Premenstrual tension is the term which Frank has designated for a not uncommon syndrome which occurs in the premenstrual phase and disappears with the onset of menstruation. It usually consists of several of the following symptoms and signs: headache, emotional instability, irritability, abdominal distention, nausea and vomiting, increased sex desire, pruritus and swelling of the vulva. Many women, however, suffer from moderate degrees of such disturbances but these are usually accepted without question as a normal feature of the menstrual cycle. For the sake of convenience we have termed the latter condition "premenstrual distress." It is our belief that both premenstrual distress and premenstrual tension have a common etiology, the difference between the two being a quantitative one. We have postulated that both are the result of changes in the electrolyte and water balance of the various tissues of the body which are probably the result of cyclic ovarian activity.