There are many clinical causes of leukocytosis, ranging from physiological to pathological factors. Because leukocytes are immune cells, they are an immune response produced by the body in a state of stress. Therefore, there are some normal physiological conditions in the body that can lead to an increase in leukocytes, such as strenuous exercise, satiety or poisoning, blood concentration, including heat stroke, which can cause an increase in leukocytes. In addition, clinical pathological factors can also lead to leukocyte increase, the most common factor is the blood bone marrow system diseases, such as common leukemia, myelodysplastic syndrome, etc. will lead to leukocyte increase. Some clinical drugs can also cause leukocytosis, such as drug poisoning or special drugs, such as shark liver alcohol, B4 overdose, will also play a role in raising leukocytes, which can also lead to an abnormal increase in leukocytes. Some clinical diseases can also cause leukocytosis, the most common being infections. Infections clinically common other than viruses, other infections can cause, such as bacteria, protozoa, fungi, etc. can cause leukocytosis, is also the most common cause of clinical leukocytosis.