Fever after 4 days of cryptorchid surgery for a 5-year-old boy may be caused by infection, and patients can improve their condition through general treatment, medication and physical therapy. 1. General treatment: when the child has urinary tract infection or wound infection after surgery, it may cause fever, patients should pay attention to rest, do a good job of wound care, drink more water, pay attention to replenish body fluids, to avoid dehydration caused by high fever. 2. medication: children can take antibiotics under the guidance of the doctor, such as cefixime, amoxicillin and other anti-infective treatment, you can also use iodophor, hydrogen peroxide and other disinfectant drugs for local application, if the symptoms of high fever is more serious, you can take non-steroidal drugs, such as ibuprofen suspension, etc. for treatment. 3. Physical therapy: children with fever can be physically cooled down by rubbing their bodies with warm water and applying fever-reducing patches, and their body temperature can be closely monitored. If the symptoms are not relieved for a long time or continue to aggravate, you should consult a doctor for urine routine, urine culture, blood routine and other aspects of the examination, to clarify the cause of the targeted treatment, in addition to recommending that the patient pay attention to supplemental nutrition, appropriate food rich in protein, vitamins, and to avoid eating spicy and stimulating food.