RESUMEN
<b>Objective</b>: The psychophysiological and immunological effects of exposure to different varieties of essential oils on fatigue were extensively investigated in students performing personal computer tasks.<br> <b>Design</b>: Randomized crossover study<br> <b>Methods</b>: This study was approved by the Kyoto Prefectural University of Medicine Research Ethics Committee, and informed consents were obtained from all subjects. Eight healthy male university students with mean age of 22.38±1.30 (range 21–24) who served as the subjects in this study were given a 120-minute personal computer task with 10-minute rest period before and after the task.<br> During the course of performing PC task, subjects were either exposed to one of the five essential oil odors (grapefruit, peppermint, true lavender, blend A, blend B) or not exposed to any odor at all, serving as the control in the study. Each of the six odor setting were carried out on separate days upon which psychophysiological and immunological parameters of fatigue in the subjects were evaluated.<br> <b>Results and Conclusions</b>: The results of this study suggest that exposure to essential oil odors affects the autonomic nervous and immunological system when engaged in a personal computer task. Moreover, different varieties of essential oils cause different vital reactions. In particular, peppermint essential oil exhibits fatigue-reducing effects.<br>