Introduction and Objectives: According to Sternberg, three dimensions of love is rarely possessed by an individual equally at a time and the extent of each one of these dimensions varies in romantic relationship. He also points out that intimacy, passion and desire and decision/ commitment create 8 different types of love combined. Each one of these features has its own advantages and disadvantages, while some types of love are associated with higher levels of satisfaction. So the present research aims to examine the effect of love on stress level. Method: In this research, using available sampling method and given the criteria for entering the study, 60 students of ninth grade were selected. The questionnaire was distributed among them, and then, 42 individuals who were in love were chosen. Then, ELISA method was used to measure cortisol concentration. Control samples were taken early in the morning to determine level of cortisol in the fasting students, at the same time, other tests (blood pressure, blood glucose and heart rate measurements) were performed. Then, students were allowed to spend time with their friends for two and half hours. In the next step, the same experiments were conducted. In this research we used Eviews Software and regression analysis for data analysis. Findings: Results showed that intimate friends lower each other's stress level and reduce the salivary cortisol by an average of 31 ng/ml when they spend time with each other. However, ordinary friends do not have significant effect on each other. Conclusion: According to the results of this research, true and appropriate types of love are one of the ways to avoid stress and concerns of life.
