We evaluated the efficacy and safety of three doses of a novel alprostadil cream in a randomized, double-blind, placebo-controlled study in 94 women presenting with female sexual arousal disorder of at least 6 month s duration. We sent the subjects home with 10 premeasured doses of 500 g, 1000 g, or 1500 g alprostadil or a placebo cream to be applied to the vulvar area prior to vaginal intercourse over a period of 6 weeks. The primary efficacy parameter, the arousal success rate (as measured by diary responses to the Female Sexual Encounter Profile [FSEP]), was highest in the alprostadil 1000 g group and lowest in the 500 g group, but the responses were not different from that of the placebo cream, at the p = 0.05 level, for any of the three alprostadil doses. However, the change from baseline for Item 6 of the Female Sexual Function Index (FSFI; Rosen et al., 2000; satisfaction with arousal during sexual activity) suggested an important dose-related trend (p = 0.173; 1500 g versus placebo). The mean percent responder rate (responder = > 50% arousal success rate with > 3 sexual attempts) suggested a dose-response effect (p = 0.157; 1500 g versus placebo). Adverse events were generally mild or moderate in intensity and mainly involved localized reactions in the genital area.