Study aim: Investigating the effect of vitamin D suppositories on the sexual function of postmenopausal women Design: In this study, 105 postmenopausal women (with inclusion criteria) will be recruited in the study. Using a simple randomization method, participants will be assigned in three study groups. To execute simple randomization method, the assignment sequence will be written before the beginning of the research, and then participants will be assigned in one of three groups of intervention, placebo and control. Settings and conduct: Participants of the study will be selected among the clients of the comprehensive health centers of Bouyin Zahra.for the purpose of blinding, the assignment and coding sequence will be written by a person who is not in the research group and the codes will be concealed until the end of the analysis. in this way, participants, researcher and analysor will be blinded. Participants/Inclusion and exclusion criteria: Inclusion criteria: postmenopausal women, the absence of other diseases of the gland, such as diabetes and ... Exclusion criteria: hormone therapy, stressful experience during the last 3 months Intervention groups: There is three study groups: intervention group receiving vitamin D3 suppositories; control group receiving placebo suppositories, and control group receiving no intervention. Main outcome variables: Postmenopausal women's Sexual function