SummaryTwo patients are described with acute streptococcal myositis. One of them died after a brief duration of illness in multiple organ failure; the other survived extensive muscular damage complicated by diffuse intravascular coagulation, acute renal failure, adult respiratory distress syndrome, bronchopneumonia, Pseudomonas septicaemia and probably streptococcal toxic shock syndrome. Both patients received nonsteroidal antiphlogistics, purportedly involved in the pathogenesis of this syndrome. Based on a mouse model, clindamycin would seem to be the antibiotic of choice.