Approximately half of the 40-50% of North American women who crave chocolate or sweets do so principally in the perimenstrum, the part of the menstrual cycle surrounding the onset of menstruation. We test two hypotheses about the events that trigger these cravings: 1) the premenstrual drop in progesterone levels; or 2) dysphoria or tension in the perimenstruum. Chocolate craving, sweets craving, and other perimenstrual symptoms were rated daily for six menstrual cycles by a sample of women with severe premenstrual syndrome (PMS). Forty-four women satisfied criteria for cyclicity in chocolate craving, and 44 for sweet craving, determined during the first two cycles. Thirty-four subjects satisfied criteria for craving of both chocolate and sweets. After placebo treatments during the third cycle, subjects were randomly assigned, double blind, to administration of placebo, oral micronized progesterone, or alprazolam (a tranquillizer). Treatments were administered from the beginning of the third week to the second day postonset of menstruation during the fourth to sixth months of study. Neither progesterone nor alprazolam decreased chocolate or sweets craving.