Group A streptococcus (GAS) is a β-hemolytic bacterium often found in the throat and skin. The two most severe clinical manifestations of GAS are streptococcal toxic shock syndrome and necrotizing fasciitis. Intravenous immunoglobulin (IVIg) is a gamma globulin made from purified pooled plasma of thousands of donors, consisting mainly of IgG. We report the case of a 40-year-old man admitted after 2 days of vomiting and severe right-sided chest pain. He was hypotensive with a sinus tachycardia, pyrexial, and vasodilated. The only other positive finding was a swollen and erythematous chest wall. Muscle layer biopsies and blood cultures soon grew extensive GAS, and an initial diagnosis of necrotizing fasciitis was made. The clinical syndrome was of severe septic shock secondary to invasive GAS. The patient quickly deteriorated with a worsening metabolic acidosis. Despite maximal intensive care therapy including fluids, vasoactive agents, and also activated protein C, the patient continued to remain profoundly hypotensive. A decision was made to commence IVIg, with the aim of immunomodulation of the inflammatory cascade seen in sepsis. Over the next 24 hours the patient improved, was extubated 3 days later, and subsequently discharged from hospital after 2 weeks. Although the evidence for the use of IVIg in severe invasive GAS disease is limited, we feel that on reviewing the available literature its use in this case was justified. The limited worldwide supply and high costs, together with a limited evidence base, warrant restricting its use to cases in which conventional therapy has failed. The literature for use of intravenous immunoglobulin in invasive GAS infection will be reviewed in this article.