Many patients with EBV infection, mostly young adults (between 15-25 years old), are previously fit, have a history of exertion or cold before the onset of the disease, have high fever, sore throat, and local lymph node enlargement as the main symptoms, and have poor antibiotic treatment, with some combined with abnormal liver function. Most of these patients recover within 7-14 days through rehydration, liver protection, fever reduction, and symptomatic treatment. Another part of the disease is EBV infection in the elderly, which presents with recurrent fever and sore throat, with or without lymph node enlargement, and antibiotics are ineffective. EBV infections in the elderly have a long course of several months to half a year because of the poor immunity of the body. A 60-year-old man admitted to our department had a series of tests (at a cost of tens of thousands of dollars) and expensive antibiotics in a foreign hospital for long-term fever, and was finally diagnosed with EBV infection in our department. It is recommended that patients with fever should improve their leukocyte classification (EBV infection should be considered if there is an increase in heterogeneous lymphocytes), blood EBV DNA test and EBV antibody test when checking blood leukocytes with significantly elevated monocytes. Do not apply antibiotics blindly to avoid the financial burden and unnecessary side effects of drugs.