Sensory and affective pain discrimination after inhalation of essential oils.

OBJECTIVE The purpose of this investigation was to examine the effects of olfactory absorption of two commonly used therapeutic essential oils on sensory and affective responses to experimentally induced pain. METHODS A sex-balanced (13 men and 13 women) randomized crossover design was used to obtain pre- and posttreatment change scores for quantitative sensory ratings of contact heat, pressure, and ischemic pain across separate inhalation treatment conditions using essential oil of lavender, essential oil of rosemary, and distilled water (control). Subjective reports of treatment-related changes in pain intensity and pain unpleasantness were obtained for each condition using a visual analog scale. We interpret our findings with respect to the separate dimensions of sensory and affective processing of pain. RESULTS Analyses revealed the absence of changes in quantitative pain sensitivity ratings between conditions. However, retrospectively, subjects' global impression of treatment outcome indicated that both pain intensity and pain unpleasantness were reduced after treatment with lavender and marginally reduced after treatment with rosemary, compared with the control condition. CONCLUSION These findings suggest that aromatherapy may not elicit a direct analgesic effect but instead may alter affective appraisal of the experience and consequent retrospective evaluation of treatment-related pain.