In the battery of diseases caused by group A streptococci, streptococcal toxic shock syndrome is among the most severe. Its nonspecific presentation and rapid progression require that the treating physician be both knowledgeable and vigilant. Certain signs and symptoms suggest that caution is in order: Pain out of proportion to physical findings may herald deep tissue involvement in a patient who at first glance appears to have cellulitis. Streptococcal infection accompanied by hypotension, confusion, or unexplained acute renal insufficiency is a clue to streptococcal toxic shock syndrome. Treatment consists of antibiotic and supportive care, with aggressive surgical debridement of soft-tissue foci of infection when necessary. Anecdotal evidence suggests that intravenous immunoglobulin may have a place in neutralizing the secreted streptococcal toxins that are thought to mediate features of the disease. At present, even with aggressive therapy, the mortality rate of streptococcal toxic shock syndrome can exceed 50%. Understanding of its pathogenesis is progressing. However, until effective interventions are developed, early detection appears to be the best weapon.