absorbed through the body by inhalation with plasma Material and Method level reaching a maximum peak in approximately seven Subiects minutes after administration,which can cause a Twenty selected participants equal number depression of nervous system.Linalyl acetate has a of male and female aged between 18 and 35 years narcotic action and linalool acts as a sedative(5.6) (mean age 23.25+4.52 years)with normal body mass Diego et al(found that individuals felt more relaxed indices(mean 20.86+1.91)were enrolled in the present and an improved mood after inhaling lavender oil. study.A summary of the demographic data of the Moreover,an increase of mid frontal(F3,F4)alpha participants is presented in Table 1.All participants power on their EEG was found after inhalation of the were right-handed as determined by the Edinburgh oil(s).Motomura()suggests that lavender has been Handedness Inventory(4).None of the subjects had demonstrated to decrease stress scores and increase abnormalities affecting smell,cardiovascular diseases. Theta 1 (3.5-5.5Hz)brain wave activity and decrease or a history of smoking or drug addiction.Subjects Betal(13.5-20 Hz)which is associated with relaxation were screened for a normal sense of smell using the In contrast,Masago1)found that there was a partial n-butyl alcohol test method(s)(mean score10+0.77). decrease in alphal (8-11Hz)activity and a significant Twelve hours prior to testing subjects were asked to decrease in posterior temporal lobe activity after wash their hair without any spray.They were also asked receiving lavender oil.Some researchers studying not to use antiperspirants,perfumes and refrain from autonomic nervous system activity also showed consuming alcohol,cigarettes,or caffeinated drinks. contrasting results.For example,Tongnit et al found Women who were menstruating were not included a significantly decreased blood pressure,heart rate in the sample(16).They were requested to try to sleep and respiratory rate caused by three minutes inhalation well before the day of the experiment to avoid of lavender essential oils,whereas Sriboon(2)found feeling fatigued or drowsy.Subjects were given a full inhalation lavender oil by aroma lamp caused a explanation of the research and a written informed significant decrease in respiratory rate and subjective consent of all aspects of the present study,and were calmness and relaxation,but diastolic blood pressure free to withdraw at any time. and heart rate increased.These results might be due to The present study was approved by the hedonic effect (pleasant and unpleasant).In the Ethical Review Committee for Research Involving research by Brauchli et al)they reported that heart Human Research Subjects,Health Science Group, rate is an autonomic variable that can be affected by Chulalongkorn University,Permissions No.COA pleasant and unpleasant oils.For example,valeric acid NO.0092011. (judged unpleasant)can increase heart rate,while the heart rate decreases with phenylethyl alcohol(rated Essential oil administration pleasant).Therefore,the differences between stimulant The oil of lavender was obtained from the aromas and sedative aromas that can affect the pattern Thai China Flavours and Fragrances Company.The oil ofheart rate are affected by two important factors,the composition was identified by gas chromatography/ characteristic of the essential oil and its pleasantness. mass spectrometry (GC/MS)(Thermo Finnigan Many researchers studied the effect of model Trace GC Ultra equipped with Finnigan DSQ lavender oil on the brain wave activity,the autonomic MS detector.USA).The constituent of the oil were nervous system,and mood states(5).However,these identified matching their mass spectra and retention findings were often contradictory.Furthermore,some times indicated with NISTO5 MS library and the studies only investigated the activities in just two percentage compositions were computed from GC peak dimensions(10-12).Investigations of the effects of lavender oil in the three dimensions of brain wave Table1.Demographic data for the volunteers activity,the autonomic activity,and mood responses have rarely conducted.Consequently,the present Parameters Minimum Maximum Mean SD study seems to be the first experiment to examine the effects of lavender on central nervous system, Age 20 18 38 23.254.52 autonomic nervous system,such as heart rate,blood Height(cm) 20 152 17 167.436.82 pressure,breathing rate,and skin temperature,and Weight(kg) 20 46 771 58.576.38 an assessment of mood states using an inhalation Body mass index 20 17.85 24.71 20.861.91 Smell test 20 9 11 10.000.77 technique J Med Assoc Thai VoL 95 No.4 2012 599J Med Assoc Thai Vol. 95 No. 4 2012 599 absorbed through the body by inhalation with plasma level reaching a maximum peak in approximately seven minutes after administration(7), which can cause a depression of nervous system. Linalyl acetate has a narcotic action and linalool acts as a sedative(5,6). Diego et al (8) found that individuals felt more relaxed and an improved mood after inhaling lavender oil. Moreover, an increase of mid frontal (F3, F4) alpha power on their EEG was found after inhalation of the oil(8). Motomura(9) suggests that lavender has been demonstrated to decrease stress scores and increase Theta 1 (3.5-5.5Hz) brain wave activity and decrease Beta1 (13.5-20 Hz) which is associated with relaxation In contrast, Masago(10) found that there was a partial decrease in alpha1 (8-11Hz) activity and a significant decrease in posterior temporal lobe activity after receiving lavender oil. Some researchers studying autonomic nervous system activity also showed contrasting results. For example, Tongnit et al(11) found a significantly decreased blood pressure, heart rate and respiratory rate caused by three minutes inhalation of lavender essential oils, whereas Sriboon(12) found inhalation lavender oil by aroma lamp caused a significant decrease in respiratory rate and subjective calmness and relaxation, but diastolic blood pressure and heart rate increased. These results might be due to hedonic effect (pleasant and unpleasant). In the research by Brauchli et al(13), they reported that heart rate is an autonomic variable that can be affected by pleasant and unpleasant oils. For example, valeric acid (judged unpleasant) can increase heart rate, while the heart rate decreases with phenylethyl alcohol (rated pleasant). Therefore, the differences between stimulant aromas and sedative aromas that can affect the pattern of heart rate are affected by two important factors, the characteristic of the essential oil and its pleasantness. Many researchers studied the effect of lavender oil on the brain wave activity, the autonomic nervous system, and mood states(5). However, these findings were often contradictory. Furthermore, some studies only investigated the activities in just two dimensions(10-12). Investigations of the effects of lavender oil in the three dimensions of brain wave activity, the autonomic activity, and mood responses have rarely conducted. Consequently, the present study seems to be the first experiment to examine the effects of lavender on central nervous system, autonomic nervous system, such as heart rate, blood pressure, breathing rate, and skin temperature, and an assessment of mood states using an inhalation technique. Material and Method Subjects Twenty selected participants equal number of male and female aged between 18 and 35 years (mean age 23.25 + 4.52 years) with normal body mass indices (mean 20.86 + 1.91) were enrolled in the present study. A summary of the demographic data of the participants is presented in Table 1. All participants were right-handed as determined by the Edinburgh Handedness Inventory(14). None of the subjects had abnormalities affecting smell, cardiovascular diseases, or a history of smoking or drug addiction. Subjects were screened for a normal sense of smell using the n-butyl alcohol test method(15) (mean score10 + 0.77). Twelve hours prior to testing subjects were asked to wash their hair without any spray. They were also asked not to use antiperspirants, perfumes and refrain from consuming alcohol, cigarettes, or caffeinated drinks. Women who were menstruating were not included in the sample(16). They were requested to try to sleep well before the day of the experiment to avoid feeling fatigued or drowsy. Subjects were given a full explanation of the research and a written informed consent of all aspects of the present study, and were free to withdraw at any time. The present study was approved by the Ethical Review Committee for Research Involving Human Research Subjects, Health Science Group, Chulalongkorn University, Permissions No. COA NO.009/2011. Essential oil administration The oil of lavender was obtained from the Thai China Flavours and Fragrances Company. The oil composition was identified by gas chromatography/ mass spectrometry (GC/MS) (Thermo Finnigan model Trace GC Ultra equipped with Finnigan DSQ MS detector, USA).The constituent of the oil were identified matching their mass spectra and retention times indicated with NIST05 MS library and the percentage compositions were computed from GC peak Parameters n Minimum Maximum Mean SD Age 20 18 38 23.25 4.52 Height (cm) 20 152 17 167.43 6.82 Weight (kg) 20 46 771 58.57 6.38 Body mass index 20 17.85 24.71 20.86 1.91 Smell test 20 9 11 10.00 0.77 Table1. Demographic data for the volunteers