Usually 30 minutes after the patient is physically cooled, the temperature can be measured again, and most patients’ temperatures will drop. If the temperature does not drop within 24 hours, prompt medical attention is required. If the patient is in a high or ultra-high fever state, physical cooling is not the only thing to be relied upon, but medication is also needed to promote a decrease in temperature. In addition, there is no clinical basis for the specific time to reduce fever after physical cooling is given, and it is often related to a variety of factors, as follows: 1. mode: the effect of physical cooling varies with the mode of physical cooling; 2. area: if the area for physical cooling is larger, the cooling effect is better, but attention should be paid to the patient’s tolerance; 3. time: the treatment time has a direct impact on the effect of physical cooling, and usually its effect increases with time 4, temperature: including the temperature of cold therapy items used for physical cooling and the temperature of the environment; 5, site: the effect of physical cooling is different for different thicknesses of skin, and physical cooling is more effective in areas with thinner skin; 6, individual differences: infants and children have an imperfectly developed nervous system and have a lower tolerance for physical cooling; the elderly, due to reduced sensory function The response to cold stimulation is slower. In addition, women are more sensitive to cold stimulation than men.