精油在芳香療法中占有相當重要的地位，精油宣稱具有紓解壓力及消除疲勞之功效，但缺乏科學驗證，其功效無法獲得證實。本研究目的係使用腦波及心率變異度測定等生理量測技術，以評估精油吸入對消除人員心智疲勞之功效。從腦波量測數據所反映困倦水準和放鬆程度，及心率變異度變化所反映之心智負荷狀態，來評估使用不同精油對消除心智疲勞之實質功效。徵求年齡20至25歲之大學生進行實驗測試，受測對象為20人，讓受測者進行4小時左右的上課歷程後嗅聞市售精油。實驗分為三階段即課前、課後、嗅聞精油後，於各階段填寫NASA-TLX自我評估量表及量測5分鐘腦波和心率變異度。測試結果發現嗅聞精油後困倦水準下降而放鬆程度上升，表示受測者放鬆程度明顯提高。心率變異度測試結果發現嗅聞精油後，低頻成份LF下降、高頻成份HF上升，且LF/HF即交感/副交感平衡性指標有明顯下降，表示嗅聞精油後，產生顯著之放鬆作用，有利於消除疲勞。由個人主觀上心智狀態放鬆感覺之NASA-TLX評估量表，顯示精油嗅聞後優於嗅聞前。綜合上述實驗量測結果，本研究發現精油對消除心智疲勞及身心之放鬆確有顯著之功效。 Essential oil inhalation is one of the important aromatherapy. Essential oils are always used to dispel fatigue by officer workers. Owing to lack of objective measured data of the effect on dispelling fatigue for essential oil, the reliability of subjective experiment from questionnaire has always been challenged. The purpose of this study is to evaluate the effect on dispelling mental fatigue for inhaling essential oil by using physiological indices including Electroencephalogram (EEG) and heart rate variability (HRV). The basic and ratio indices of EEG power reflecting the drowsiness and relaxation levels, and the variety of HRV reflecting the condition of mental workload were used to evaluate the effect on dispelling mental fatigue substantially for inhaling different essential oils. Twenty college students aged from twenty to twenty-five years old recruited for subjects participated the experimental test. Before experimental test, the subjects must fill in NASA-TLX self-evaluation inventory and measured their EEGs and heart rate variability (HRV) for five minutes. The subjects undertook their school course about four hours and then inhaled essential oils. The study found that EEG power ratio indices (+)/ decreased and / increased after inhaling essential oils. It demonstrated that the subjects inhaled essential oils would facilitate their relaxation obviously. The result of heart rate variability showed that low-frequency component LF decreased, high-frequency component HF increased and LH/HF decreased obviously after inhaling essential oils. For NASA-TLX rating scales measurement, the participants subjectively felt more relaxed. It revealed that the subjects had remarkable effect to dispelling mental fatigue after inhaling essential oils. To summarize as mentioned above, our study found that essential oils had obvious effect on dispelling mental fatigue and facilitating relaxation.