Generally in the clinical surgery about three days is the infection period or infection latent period, clinical surgery usually within three days, the body temperature does not exceed 38.5 ℃ can be interpreted as absorption of heat, the emergence of hypothermia body temperature is mostly below 38.5 ℃, at this time, most do not do special treatment, usually using physical hypothermia and other symptomatic treatment. More than three days, if the body temperature exceeds 38.5 ℃, it usually indicates that the body is infected, or even pus, and the infected parts are mainly in the surgical incision, lungs and abdominal cavity. Therefore, the general period of infection is within three days after surgery. If the surgery is abdominal surgery, especially when the drain is placed, it is necessary to keep the drain open and draining, otherwise the blood and fluid accumulated in the abdominal cavity is a good bacterial culture medium, which is easy to cause secondary infection in the abdominal cavity, and it may even cause restrictive peritonitis.