In a normal person, if the patient’s blood test indicates more than 20,000 white blood cells, this condition is most often caused by inflammatory infections, usually caused by bacterial infections are more likely. In addition to elevated white blood cells, the patient will also have elevated neutrophils. In this case, the patient needs to identify which part of the body is infected with bacteria, and what strain of infection is possible. If necessary, if body fluids such as sputum or incisional secretions can be obtained, active bacterial culture and drug sensitivity testing should be performed. Initially, patients need to apply broad-spectrum antibiotics for anti-inflammatory treatment based on empirical medication. In the later stage, if the results of the drug sensitivity test are available, the patient should choose a sensitive antibiotic for active anti-inflammatory treatment according to the results of the drug sensitivity test, and the treatment will be more effective. Another rare condition is the elevation of white blood cells caused by the patient’s blood system disease. In this case, the patient usually has fever, fatigue and bleeding gums, and the peripheral blood smear will reveal abnormal red blood cells, white blood cells and platelets, and if necessary, the patient needs to have a bone marrow aspiration to identify whether it is caused by an infection or a blood system disease.