This study investigated the effects of a triphasic oral contraceptive (OC) on mood and on sexual interest in a group of 45 women with premenstrual complaints. Subjects made daily ratings of mood and sexual interest for one baseline cycle and were then randomly assigned to receive either placebo or OC for 3 mo. Women who received the OC reported decreased sexual interest during the menstrual and postmenstrual phases of the cycle. The predominant effect of both the OC and the placebo on mood was one of improvement, particularly during the premenstrual phase. There was little evidence of co-variation of mood and sexual interest in either group. Although the mechanism for the adverse effects of the OC on levels of sexual interest is unknown, it...