Abstract;Objective is seeing sound stimulus effect on the body of rats. This experiment required is male wister rats. All rats were devided into three groups, each group has 5 rats, and they were placed in a hot and humid environment, modeled after rainy season in Japan, in order to create a very stressful environment to the rats. Each group, Group A, B, C, respectively, was exposed to 3 kinds of sound stimulus, Pink noise, comforting sound (Mozart-Requiem), White noise, harsh sound, and silence. We observed the effect of these sound stimuli on the body: the amount of lactic acid in the blood, hyperoxidation of brain lipid, and thiamine concentration in the liver. Group A rats exposed to "pink noise" showed less vitamin consumption than those in silence. Also they showed hyperoxidation in the cerebrum. Group B rats exposed to "white noise" showed more lactic acid increase in the blood than the other two groups and hyperoxidation increase. We conclude that "Pink noise" alleviates stress and has good effect on the body. (author abst.)