From the physiological point of view, fever is divided into the following phases: 1, the beginning of the pre-fever is the process of heat production, so this is when the fever is severe and most people have chills, which is when the muscles contract, called the pre-fever heat production period; 2, when the body temperature rises, the patient is in the fever phase, the plateau phase; 3, after the physiological regulation of the body, or the regulation of the central thermoregulation point, the body heat dissipation measures increase, such as sweating, or some drug factors cause a large amount The peak body temperature gradually decreases, so this fever is called the declining period. Fever is divided into the following types according to the fever pattern: fretting fever is when the patient’s fever fluctuates less than 1℃ a day and maintains a high plateau; flaccid fever is when a person’s fever fluctuates more than 1℃ morning and night or a day; undulating fever is like a saddle, where the patient’s fever lasts for a few days, then normalizes itself after a while, and then starts again after a few days of normalcy, going downhill from a peak and then climbing again, continuously existing; and irregular fever, where the patient’s fever is not regular. The patient’s fever is not regular, the temperature peak to the temperature trough varies every day; Periodic fever is the child’s fever is regular, such as once every five days or once every three days fever, different fever type suggests different causes, so the fever type is more important to determine the cause of fever.