Blood picture usually refers to the blood leukocyte level. Recurrent fever with normal blood leukocyte level may be caused by pathologic factors such as summer hypothermia and autonomic dysfunction. 1. Summer hypothermia: it is most common in young children who are weak and emaciated. As the thermoregulatory mechanism is not yet fully developed, recurrent fever may occur, but it is usually dominated by low-grade fever. 2. Autonomic nerve dysfunction: Due to the abnormalities of the autonomic nerve function, the balance between normal heat production and heat dissipation is broken, and long-term recurrent functional fever may occur, but it is usually low fever, such as perimenopausal syndrome. When recurrent fever occurs, systematic examination is recommended to clarify the cause of the disease.