Kaffir lime essential oil was obtained from fresh peels of Citrus hystrix (Rutaceae) by hydrodistillation and analysed by GC and GC–MS. The effects of kaffir lime oil on human autonomic and behavioural parameters after massage were investigated in this study. Forty healthy volunteers participated in the experiments. Autonomic parameters recorded were skin temperature, pulse rate, breathing rate and blood pressure. Behavioural parameters were assessed by means of visual analogue scales (VAS). The kaffir lime oil caused a significant increase in blood pressure and a significant decrease in skin temperature. Regarding the behavioural parameters, subjects in the kaffir lime oil group rated themselves more alert, attentive, cheerful and vigorous than subjects in the control group. These findings are likely to represent stimulating/activating effects of the kaffir lime oil and provide some evidence for the use of kaffir lime oil in aromatherapy, such as causing relief from depression and stress in humans. Copyright © 2007 John Wiley & Sons, Ltd.