Mononucleosis is a viral infection which can last from 6 days to several months. It is characterized initially by cold symptoms and persisting sore throat with negative throat culture, fever lasting more than 72 hours, with associated cough and occasional general fatigue. The patient should be kept at bedrest while febrile and as long as symptoms of tiredness persists. There is not treatment except high protein diet, rest and copious fluids. Tests are available ten days after the onset of the illness but are of no therapeutic value.