The duration of recurrent fever after bacterial infection varies from person to person and is mainly related to the type of bacteria, the patient’s immunity and the treatment. When the treatment is effective, the fever can be relieved in 3-5 days and may last for 2 weeks or more in severe patients. High fever occurs in bacterial infections because the bacteria themselves or the toxins released stimulate the body to produce inflammatory factors, which act on the hypothalamic thermoregulatory center to upregulate the body temperature and cause febrile symptoms. Recurrent fever can occur if the bacteria are virulent, the patient’s immunity is low, or if the key bacteria are not completely killed during treatment. If effective antibiotic treatment is administered, the fever can be reduced in 3-5 days. If the patient is not well or develops complications, the fever may not go away for 2 weeks or more. Patients who develop recurrent fevers from bacterial infections should be treated promptly to avoid delays.