The influence of essential oils on human attention. I: Alertness

Scientific research on the effects of essential oils on human behavior lags behind the promises made by popular aromatherapy. Nearly all aspects of hu man behavior are closely linked to processes of attention, the basic level being that of alertness, which ranges from sleep to wakefulness. In our stu dy we measured the influence of essential oils and components of essential oils [peppermint, jasmine, ylang-ylang, 1,8-cineole (in two different dosag es) and menthol] on this core attentional function, which can be experiment ally defined as speed of information processing. Substances were administer ed by inhalation; levels of alertness were assessed by measuring motor and reaction times in a reaction time paradigm. The performances of the six exp erimental groups receiving substances (n = 20 in four groups, n = 30 in two groups) were compared with those of corresponding control groups receiving water. Between-group analysis, i.e. comparisons between experimental group s and their respective control groups, mainly did not reach statistical sig nificance. However, within-group analysis showed complex correlations betwe en subjective evaluations of substances and objective performance, indicati ng that effects of essentials oils or their components on basic forms of at tentional behavior are mainly psychological.