Colored light is used in movies, restaurants, and other situations to create particular environments. It creates a mood and sets a stage for specific events.This study used colored light to create relaxation and stress in order to evaluate physiological reactions in the human body. In all four studies of this paper, EEG, EKG, and peripheral blood flow were recorded and observed and in the latter two studies peripheral temperature and conductance were also recorded. An audio stressor was introduced in the first three studies to evaluate the stability of the altered mood of the individuals.Considerable mood alterations were observed and were easily depicted in most of the signals recorded. Although the additional stressor did create a stress response with and without colored light, it was more severe in the absence of colored light. In the fourth study, the audio stressor was not used and it was found that colored light was a stressor in itself.