Cyclic anaphylaxis associated with menstruation.
 A middle-aged woman developed recurrent episodes of severe life-threatening anaphylaxis.
 All episodes were strikingly associated with the first day of menstrual bleeding.
 Temporary relief was achieved with indomethacin therapy.
 The patient fully recovered following abdominal hysterectomy and salpingoophorectomy.
 The possible role of sex hormones and prostaglandin F2 alpha in the pathogenesis of this problem is discussed.
