Recent reports have called attention to the reemergence of invasive group A streptococcal infection in previously healthy hosts. Epidemics have been reported from several countries and have included cryptogenic bacteremias, necrotizing fasciitis, and a toxic shock-like syndrome. Reference laboratories have noted an upswing in isolates bearing M protein types 1 and 3 in strains producing streptococcal pyrogenic exotoxin A. Recent discoveries have elucidated the immunologic mechanisms behind the production of sheck and multiorgan dysfunction by these virulent organisms.