PURPOSE: The purpose of this study was to identify the effects of the phytoncides on serum cortisol level, vital signs and life stress of college students. METHODS: This study was nonequivalent control group non-synchronized design. The subjects consisted of 60(control group: 28, experimental group: 32). The phytoncides mixed the pine(pinus sylvestris) oil with the cypress(cupressus sempervirens) oil in the same rate. In the experiment, it was put in an aroma-necklace bottle and inhaled 3 times per day(9AM, at noon, before going to bed) for 2 weeks. The data were analyzed by the SPSS version 12.0 program. RESULTS: In the experimental group systolic BP(F=15.603, p=.000), diastolic BP(F=29.489, p=.000) and serum cortisol level(F=4.968, p=.000) were significantly decreased. CONCLUSION: The phytoncides inhalation is a partly help to reduce college students' life stress. The phytoncides is the incense of the familial tree. We recommended to examine what differences between the green shower and the phytoncides inhalation for the stress reduction.