If a person does not have a fever during hospitalization and develops a fever within 48 hours after discharge, it should also be considered to be due to a nosocomial infection. There are many multi-drug resistant bacteria in the hospital, and if the patient’s resistance is poor, it is possible to contract some nosocomial infections during hospitalization, most commonly respiratory tract infections, as well as gastrointestinal tract infections and genitourinary tract infections. If you have a fever with cough and phlegm soon after discharge, consider pneumonia caused by nosocomial infection, and if you have diarrhea, consider a digestive tract infection. At this time, you should promptly go to the hospital, improve the blood routine and some inflammatory indicators, improve the culture of possible pathogens and drug sensitivity test, and choose appropriate anti-infective drugs for treatment to avoid further aggravation of the disease.