After surgery, the doctor requires the patient to take the temperature every 4 hours to observe the change of the patient’s body temperature and to detect postoperative complications such as incisional infection and lung infection in time for timely treatment. Usually, within 2~3 days after surgery, the patient’s body temperature will be mildly elevated, usually around 38 degrees Celsius, which is called “surgical fever” and “surgical fever”. This phenomenon is called “surgical fever” and “surgical fever”. The reason is that the tissue trauma and protein decomposition after surgery is absorbed, so it is also called “absorption fever”. Surgical fever is a reaction of the body to surgical trauma and is a normal physiological phenomenon that does not require special treatment. If the body temperature exceeds 38 degrees Celsius, ice packs can be given to the forehead, neck or armpit, etc. Generally, the body temperature can gradually return to normal after 2~3 days of surgery. Of course, if the postoperative temperature continues to rise above 38.5 degrees Celsius, or if the temperature returns to normal after 2-3 days of surgery, there is a risk of incisional infection, poor drainage, pneumonia or other complications. Therefore, it is very important to observe the temperature of patients after surgery. In addition, when most patients return to the ward after surgery, they may have no or low body temperature, which is due to the exposure of organs, infusion, blood transfusion and anesthesia during surgery. After taking warming measures, the body temperature will soon return to normal.