We humans are constant temperature animals, our body temperature is constant, once the body temperature is too high or too low, there will be problems, and the body temperature is too high, we are commonly known as “fever”. To understand the “fever”, we must start from the normal state of body temperature analysis. How can our human body temperature hold this way when it is normal? This involves a whole set of thermoregulatory mechanisms. First of all, there is a region in the human brain is responsible for controlling body temperature, we call this region the body temperature center, this center has an initial set value, this value is the normal body temperature, if the body temperature is lower than this value, the center will command the muscle twitch heat production, is what we feel chills, at the same time make the peripheral blood vessels contraction, skin pores contraction, reduce heat dissipation, slowly the body temperature back up again, until back to that set body temperature. until it comes back up to that set body temperature. Each species of thermostat has its own set point temperature, the human is 37 degrees. And if the body temperature is too high, this center commands the body to sweat, pores open, capillaries expand, and cool down sufficiently to return to that proper temperature. If something in the body stimulates the temperature center, the original setting goes up and the new setting may be 38 degrees, 39 degrees, 40 degrees …… all possible, depending on the strength of the stimulus and the type of stimulus. Then the original body temperature is too low at this time relatively speaking. For example, if a person has a cold, the temperature center is stimulated and the set value starts to move up, at this time, the original body temperature of 37 degrees becomes too low, the body will feel too cold, the center will command the body to produce heat, and at the same time reduce heat loss, and keep raising the body temperature, and finally rise to, for example, 39 degrees, escalating to the new set value, the center feels just right, and no longer command heat production. The body temperature is then stabilized at the new level. So what substances can stimulate the center? There are many substances that can affect, and the cold and fever mentioned earlier is caused by the most common stimulant – foreign microorganisms. The invasion of microorganisms, such as bacteria, viruses and mycoplasma, can cause fever. When the resistance is good, the invasion does not cause fever because the body immediately clears these microorganisms; but if the resistance is poor, these microorganisms multiply and stimulate the temperature center, and then fever will start. Of course these microorganisms are not directly stimulated to the body temperature center. After the invasion of microorganisms, which belong to be foreign, then the body’s immune system is activated, and the function of the immune system is to remove foreign objects and remove things that do not belong to it. After the activation of the immune system, many cells start working, mainly the white blood cells, and after activation the white blood cells release many chemicals, which we call white mediators, and these substances stimulate the center and move up the set value. But scientists further research, found that the white medium is not yet a direct stimulus to the central substances, the main stimulus should be prostaglandins, white medium stimulates various cells to synthesize prostaglandins, and finally prostaglandins body temperature central direct stimulus. In view of the fact that prostaglandins have such a role, human beings invented drugs for this substance, which can play a very good role in reducing fever.