Fever from bacterial infections can be seen in upper respiratory tract infections, pneumonia, meningitis, etc. Generally, fever from bacterial infections lasts for about 5 to 14 days, and may last up to a month if it causes an abscessed lesion. Due to the large differences between individuals, the time needed to reduce the fever varies. 1. Upper respiratory tract infection: fever caused by bacterial infection is mostly considered to be caused by upper respiratory tract infection. The patient will have fever, cough, fatigue and other symptoms. Patients with upper respiratory tract infections that are caused by bacterial infections usually have a fever for about 5~7 days. The fever can usually go down within 2~3 days. 2. Pneumonia: Pneumonia caused by bacterial infection, patients will have fever, loss of appetite, shortness of breath and other symptoms. The patient develops fever, usually in about 7~12 days. Patients may present with recurrent fever symptoms. 3. Meningitis: In meningitis caused by bacterial infection, the fever may last longer. Patients with meningitis will have fever, impaired consciousness, severe headache, vomiting and other symptoms. Generally, in patients with bacterial infection, the fever can last for 10~14 days, and its fever is not persistent, most of them show recurrent fever. 4. Bacterial infection may also cause abscess lesions such as lung abscess, pyothorax, liver abscess, etc., the lesions are not cleared fever process will be prolonged, up to one month is also possible, in addition to the body’s immunity will also prolong the fever time. It is recommended that patients once the symptoms of fever, the need for timely consultation, and actively take therapeutic measures, patients need to follow the doctor’s instructions to take medication, do not take drugs without authorization, so as not to cause adverse effects on the body.