Abstarct: Introduction: Premenstrual syndrome and dysmenorrhea are common problems in girls that are accompanied by mental and physical symptoms in the premenstrual period and menstrual pain, respectively. The aim of the present study was to investigate the effect of aerobic exercise and thyme supplementation on dysmenorrhea and premenstrual syndrome in adolescent girls. Methodology: The present study was a quasi-experimental study with a pretest and posttest design. For this purpose, 40 female high school students aged 16 to 18 years, weighing 50-54 kg and a body mass index of 19-50/20 in Kerman were selected and randomly divided into four groups: placebo, supplement, supplement exercise and control. The Mous Menstrual Distress Questionnaire was used to assess the severity of dysmenorrhea, the PSST questionnaire was used to assess the symptoms of premenstrual syndrome, and the McGill Questionnaire was used to assess pain perception. The intervention in the study included aerobic exercise with a specific intensity and duration, taking thyme supplements in the form of capsules, and a combination of both for the intervention groups. The main training consisted of 3 days a week of upper and lower body aerobic exercises for 15-25 minutes with 1-2 repetitions and 4-5 minutes of rest between each repetition, and the intensity of the exercises started at 35% and continued up to 60% of the maximum heart rate. The control group did not receive any intervention. Questionnaires were completed before and after the intervention. Analysis of covariance was used to examine the differences between groups with SPSS version 26 software. Results: The results of the analysis of covariance showed that there was a significant difference between the control group and the placebo aerobic exercise group (P=0.001), and the supplementary exercise group (P=0.001) for dysmenorrhea and premenstrual syndrome. However, no significant difference was observed for the supplementary group alone with the control group (P=0.999). Conclusion: This study shows that aerobic exercise significantly reduces the symptoms of premenstrual syndrome and dysmenorrhea, emphasizing the importance of regular physical activity in managing these problems. Also, combining aerobic exercise with thyme supplementation helped improve women's condition, while taking thyme alone had no significant effect. Therefore, it is recommended that women include aerobic exercise along with supplementation in their programs to achieve the best results.