Bacterial infections are caused by human factors and bacterial factors: 1. Human factors: When there is a break in the skin mucosa or purulent inflammation, bacteria are easy to enter the body, and when the body’s immune function reacts, it can be divided into non-specific immune response and specific immunity. Specific immunity includes bacterial immunity and humoral immunity, when the body’s immune function decreases, it cannot give full play to its role of phagocytosis and killing bacteria, it is easy to form a small amount of bacteria, resulting in pathogenic force is not strong and cause infection, the medical source of infection caused by conditional pathogenic bacteria gradually increased; 2. Factors of bacteria: mainly related to the virulence and number of pathogenic bacteria, pathogenic bacteria are virulent or a large number of enter the body to cause The possibility of sepsis is greater. Whether the bacteria invade the body to cause infection is directly related to the human defense immune function and the virulence and number of bacteria. Common clinical bacterial infections include bronchitis, infections of the upper respiratory tract, fever and urinary tract infections, etc. At this time, active measures and symptomatic medication should be taken. First of all, it is necessary to fight the infection and control the extension of clinical symptoms of the patient, then avoid affecting the health of the human body due to the infection, and at the same time actively strengthen the immune function of the human body to ensure the health of the human body.