Bacterial infection fevers typically recur for three to five days and may last two weeks or longer in severe cases. The fever is caused by bacteria that infect the body and stimulate the body to produce inflammatory mediators by themselves or by the toxins they release, which in turn stimulate the thermoregulatory center in the hypothalamus to up-regulate the body temperature, leading to fever in the body. Therefore, to reduce the fever need to kill the bacteria in the body, if the virulence of the bacteria is weak, after antibiotic treatment can generally be in 3 ~ 5 days fever, if the bacteria virulence is strong, the patient’s physical condition is not good there will be a recurring fever, it may take two weeks or even more time to reduce the fever. When the patient has recurrent fever that does not heal, it is recommended to consult a doctor in time to avoid delaying the condition.