Bypass surgery refers to heart bypass surgery, heart bypass surgery 13 days fever, may be related to postoperative reaction, postoperative infection, cold and so on, need to be based on the cause of the disease, through drug treatment, timely change of medication, life conditioning and other methods of treatment. 1. Postoperative reaction: heart bypass surgery is a kind of major surgery, in the process of surgical treatment, there will be local tissue necrosis, trauma and bleeding and other phenomena, the patient may appear necrotic material absorption fever. At this time, we need to pay more attention to observation, actively strengthen the change of medicine, regular medication, generally will recover by themselves. 2. Postoperative infection: If the site is infected after surgery, it will cause fever. You need to clean and drain the wound in time, then change the medicine regularly, and then use cephalosporin and penicillin antibiotics for treatment. 3. Cold and flu: Because the patient’s body is relatively weak after surgery, if there is no enhanced care, it may cause cold and flu and other phenomena, causing fever. If the body temperature reaches 38.5 degrees or above, oral acetaminophen, ibuprofen and other fever-reducing treatments can be taken, while replenishing fluids in a timely manner, so as to avoid a continuous rise in temperature. Family members are advised to take more care of the patient, and if they find any abnormal reaction, they need to inform the doctors and nurses in time, and strictly follow the doctor’s instructions for treatment.