The Effect of the Odor of Isovaleric Acid and Japanese Cypress on Human Immune and Endocrine Secretion – a Preriminaly Study

The effect of pleasant and unpleasant odor on human physiological state was preliminary investigated by assessing salivary substances. A term “pleasant” (or unpleasant) is rather showing one’s subjective and thus mental state meanwhile the odor itself should give an impact to both human mind and body. This study was aimed at investigating an effect of pleasant/unpleasant odors on human body and mind. In the experiment the odor of isovaleric acid, as an unpleasant odor, and Japanese cypress, as a pleasant one, were exposed to subjects for 18 minutes. Salivary immune substance (Immunoglobulin A: IgA) and glucocorticoid (cortisol) were determined every three minutes as for an indices of the impact of the odors on human immune and endocrine secretion. As a developing result, IgA showed an increase by isovaleric odor whilst cortisol decreased, even though the concentration of that unpleasant odor was too low to be aware of. These changes in the secretion of the substances were discussed in relation with human physiological stress reaction mechanism.