Background: Menopause is a critical period with frequent sexual disorders. Objectives: The current study assessed the therapeutic effect of a combination of the aerial part of Melissa officinalis, fennel fruit extract, and Nigella sativa seed powder on the sexual dysfunction of postmenopausal women. Methods: This randomized clinical trial was performed on 48 menopausal women from April 2015 to October 2017. The participants included the menopausal women referring to the clinic of Gorgan health centers aged between 41 and 54 years with natural menopause (amenorrhea for at least 12 months) and discomfort in sexual activity. They were randomized into two treatment groups. Group 1 (n = 27) received 1000 mg capsules (Melissa officinalis, fennel extract, and Nigella sativa powder), and group 2 (n = 21) received a placebo (1000 mg starch capsules (in an eight-week course of treatment (one capsule per day for each group). The variables in the female sexual function index (FSFI) questionnaire were compared in the two groups before and after the intervention. Results: The results showed that the mean scores of sexual dysfunction in the domains of arousal, lubrication, orgasm, satisfaction, and pain were not significantly different between the two groups (P > 0.05). Conclusions: Despite many studies on the effectiveness of Melissa, Foenculum, and Nigella, this study showed that a combination of Foeniculum vulgare, Melissa officinalis extract, and Nigella sativa seed powder does not improve the sexual function of postmenopausal women with sexual dysfunction, and it might be the synergism effect of this combination.