Beginning in the mid-1980s, an epidemic of severe invasive infections caused by Streptococcus pyogenes (S. pyogenes), also known as group A streptococcus (GAS), occurred in the United States, Europe, and elsewhere. Potent cytotoxins produced by this human pathogen contribute to the infection, commonly known as ‘flesh-eating disease.’ A new study reports that the bacteria’s full virulence is dependent on the presence of two specific cytotoxins, NADase (SPN) and streptolysin O (SLO).