The cause of much inflammation in the body is the defense reaction due to the stimulation of the organism by infectious factors, physical factors, necrotic tissues and so on. 1. Infectious factors: Inflammation occurs due to the invasion of viruses and bacteria into the organism and their reproduction in the body. Patients will have symptoms of fever and chills, and in severe cases, diseases such as pneumonia and hepatitis may occur. 2. Physical factors: due to severe trauma, burns and major surgery after the body’s immunity is reduced, the wound has ooze or fluid accumulation caused by infection, which in turn leads to the occurrence of inflammation. As the patient is bedridden for a long time after burns or surgery, diseases such as crashing pneumonia or urinary tract infection may occur. 3. Necrotic tissue: due to blood circulation disorders in the body, resulting in necrosis of skin tissues due to ischemia and hypoxia, and necrotic tissue is a potential inflammatory factor, so inflammation will occur. Patients will have symptoms of fever due to inflammation and gangrene in severe cases. Inflammatory reactions in the body may also be due to other reasons, and it is recommended that patients go to the hospital in time for examination to clarify the cause of the disease and then follow the doctor’s instructions for treatment.