It is considered that olfactory stimulation by fragrance inhalation is one of the methods of relaxation. We examined the possibility by using fragrance inhalation essential oils, such as sweet orange oil and peppermint oil. We measured salivary alpha-amylase activity and state anxiety levels in undergraduate students before and after inhalation. Salivary alpha-amylase activity levels have been utilized to assess the sympathetic nervous activity.
Our results indicate that both salivary alpha-amylase activity and state anxiety levels are significantly reduced after fragrance inhalation of the sweet orange oil. Consequently, our research suggests that sweet orange essential oil has a relaxation effect.