Staphylococcus aureus D4508, obtained from a patient with nonmenstrual toxic shock syndrome (TSS), produced enterotoxin A while not making other known enterotoxins or TSS toxin 1. Concentrated culture fluids of the organism, administered subcutaneously in miniosmotic pumps, induced TSS-like symptoms (four of six animals succumbed). Identical culture fluids pretreated with anti-enterotoxin A serum failed to induce symptoms except for fever (none of six animals succumbed). Purified staphylococcal enterotoxin A also had the ability to induce TSS-like symptoms. These data suggest that enterotoxin A is the major TSS-associated toxin made by strain D4508.