Introduction In spite of its importance, the psychological health requirements of adolescents are ignored; due to the occurrence of mental disorders in this age group and also public interest in the use of supplementary and alternative treatments such as herbal drugs for mental disorders, this study was carried out aimed at examining the impact of the Melissa officinalis capsule on the psychological health of female adolescents. Methodology In this randomized clinical trial study, 100 female adolescents were assigned to two groups of either drug and placebo groups. The data collection tool includes demographic information recording note and General Health Standard Questionnaire (GHQ). Intervention has been done in the menstrual cycle during 3 successive months and patients received two 600 mg drug daily in the intervention group, and the control group received placebo. After the intervention, the scores of the participants' psychological health were measured in both groups and data were analyzed through independent t-test using SPSS software version 16. Results The study results showed that psychosomatic symptoms score (p < 0.001), anxiety and sleeping disorder (p < 0.001), and social function disorder (p = 0.021) in the experiment group was significantly less than that of the placebo group. Conclusion Based on the findings of this study, Melissa officinalis can decrease psychosomatic symptoms, sleeping disorder and anxiety, depression and disorder in social function in female adolescents.