A thermometer of 37.8°C without symptoms may be due to physiologic or pathologic factors. The thermometer measured 37.8°C, indicating that the body temperature is high. Physiological factors that cause an increase in body temperature generally include after meals, after strenuous exercise, high temperature environments, overdressing, and mental overstress. All of these can cause the body temperature to rise, but there will not be obvious symptoms, through rest, cool, stabilize emotions, drink plain water can make the body temperature return to normal. If the above reasons are excluded and the body temperature is measured at 37.8°C, even if there are no symptoms, it should be considered to be a pathologic cause. For example, some elderly people suffer from colds or urinary tract infections, etc., which often have no obvious symptoms due to their poor sensitivity to the rise in body temperature. Some infants, children patients, often the onset of early or mild fever will not be expressed, and there are no obvious symptoms, may be when the body temperature continues to rise only after the appearance of poor mental health, lethargy, loss of appetite and so on. Therefore, the thermometer 37.8 ° C first to exclude physiological factors and the thermometer itself, and then go to the hospital to find the cause of the fever, a clear diagnosis, and then follow the doctor’s instructions to standardize the treatment.