Peppermint oil and eucalyptus oil preparations were found to have benefical neurophysiological and psychological effects on 32 healthy subjects in a double-blind, placebo-controlled, randomized cross-over design study.
Four different preparations were applied to large areas of the forehead and temples using a small sponge and their effect was then evaluated. The combination of peppermint oil, eucalyptus oil and ethanol increased cognitive performance and had a muscle-relaxing and mentally relaxing effect, but had little influence on pain sensitivity. However, peppermint oil and ethanol combined produced a significant analgesic effect with a reduction in sensitivity to headache. The researchers concluded that the essential oil preparations can be shown by laboratory tests to exert significant effects on the body’s mechanisms associated with headaches.
Gobel H; Schmidt G; Soyka D. Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters. Cephalalgia (NORWAY) Jun 1994, 14 (3) p228-34