There are many experiments about the deodorant effects of essential oils. However, those mostly depend on chemical analysis and subjective evaluation. The physiological effects of those have not been studied using physiological indicators. When evaluating stimulation using subjective evaluation, the results must be re-interpreted by recalling them. In addition, different persons assign different meanings to an expression. A physiological indicator that allows objective and continuous evaluation of the status of the body under stimulation has been attracting attention as an important evaluation method for interpreting the status of the body. In this study, we used physiological indicators and psychological evaluations about the deodorant effect of an essential oil and tested it. Consecutive blood pressure and brain hemodynamics were examined with physiological indicators. Subjectivity evaluation using the smell strength and the unpleasantness degree were performed to determine changes in psychological impression. The bad smell of excreta gave subjects unpleasantness, and the systolic blood pressure and brain hemodynamics of the subjects' prefrontal area increased. The subjects' unpleasantness disappeared when they mixed eucalyptus oil with the bad smell, and the systolic blood pressure and brain hemodynamics became stable. The above demonstrates that eucalyptus oil has physiological and psychological deodorant effects. Eucalyptus oil will be useful for development of fragrance and deodorant products.