Background: Menstruation is a landmark in every female's life. Premenstrual syndrome is a particularly commonest gynecological complains in adolescent stage, in Egypt the prevalence of PMS was found to be (89.6 %) among medical students of Ain Shams University. The aim of this study was to assess the effect of cinnamon on physical symptoms of premenstrual syndrome among adolescent girls at Mansoura University. A quasi-experimental research design was utilized. The study setting was conducted at nursing School of Mansoura University. A purposive sample of 150 students complains from premenstrual syndrome from September 2012 to May 2013 study that served as a one arm intervention. Three tools were used to collect data, the first tool; was structured questionnaire sheet, the 2nd tool was the present assessments tool to assess severity of physical symptoms of PMS and the third tool was satisfaction Likerts scale for measure the level of student's satisfaction from using cinnamon as a way of relieving physical symptoms. The Results: More than half (52%) of nursing school students had menarche at age 10, also around half 41.3% of students were sever general body discomfort while more than half of them 56% have moderate abdominal pain pre-intervention. After intervention by using cinnamon there were highly significant positive effects to decrease symptoms from baseline to post dairy one and post dairy two. It's clearly the association that highly significantly positive relationship between the reductions of severity of physical symptoms and regularity of taking cinnamon, also approximately three quarter of the student were satisfied from the positive effect of cinnamon. Conclusion: There were highly significant positive effect in reduction of severity of PMS physical symptoms after regular taking cinnamon packet supplementation and most of students were satisfied from the effect of the cinnamon. Recommendation: Raising the awareness of adolescent girl about the safety and efficacy of a herbal therapy especially cinnamon