Abstract： Objective:To analyze the diagnosis and treatment process of one case of neutropenia with fever caused by substitution of linezolid for vancomycin,and provide a reference for the safe use of linezolid and vancomycin in clinical practice.Methods and Results:The patient was admitted to the hospital due to"right knee pain and limited mobility caused by trauma for 9 days".Arthroscopic examination of the knee joint showed purulent arthritis,and vancomycin was administered empirically.Subsequent culture of the joint drainage fluid did reveal methicillin-resistant Staphylococcus aureus.After ten days of vancomycin treatment,the results of blood and joint drainage fluid cultures were negative,however,the patient still had intermittent fever,and the neutrophil count was progressively decreasing to 1.29×109/L.After consultation with the infectious disease experts,it was believed that the neutropenia and fever were possibly caused by vancomycin,and it was suggested to use linezolid.Within one week after administration of linezolid,the neutrophil count continued to decrease,even falling below 0.1×109/L.Therefore,linezolid was immediately discontinued and recombinant human granulocyte colony-stimulating factor was administered.Three days later,the neutrophil count recovered significantly,and 13 days later,the neutrophil count returned to normal level without further decline.Conclusion:Neutropenia caused by non-chemotherapy drugs is a serious adverse drug reaction.Vancomycin and linezolid can both cause neutropenia.Clinically,the adverse drug reactions should be monitored and neutropenia without other obvious inducements should be concerned,so as to ensure the safe medication for patients.