Four cases of lemierre's disease, or post-anginal (anaerobic) sepsis, are presented. All of the patients had polymicrobial infections. Two of the patients had serologically confirmed infectious mononucleosis. All patients required intubation and mechanical ventilation due to severe respiratory insufficiency. Two patients died after the development of severe septic shock with multiple organ dysfunction. The pathogenesis and clinical manifestations as well as the management of post-anginal sepsis are discussed.