The relationship between physiological and psychological indices was investigated when the color of the environment (red, blue, or yellow) was changed. An evaluation indexA visual analogue scale (VAS) was used as the psychological index, while nasal skin temperature was used as the physiological index. Figure 1 shows an example of a VAS.Abstract Since colors affect human beings both physiologically and mentally, various studies have been conducted about the infl uences of color. Most of the studies have been focused on the psychological aspects. In this study, we investigated the infl uences of color physiologically by the use of infrared thermography. With this technique, the subjects wear no devices, and objective values are expected to be obtained to evaluate the infl uences of color. Nasal skin temperatures were measured by infrared thermography under yellow, red, and blue illuminations. A signifi cant temperature change was observed under red illumination.