Staphylococcus aureus superantigenic toxins are responsible for menstrual and non-menstrual toxic shock syndrome (TSS). We compared the clinical and biological characteristics of 21 cases of menstrual TSS (MTSS) with 34 cases of non-menstrual TSS (NMTSS) diagnosed in France from December 2003 to June 2006. All 55 S. aureus isolates had been spontaneously referred to the French National Staphylococcal Reference Center, where they were screened for superantigenic toxin gene sequences. Most of the patients had previously been in good health. The most striking differences between MTSS and NMTSS were the higher frequency in NMTSS of neurological disorders (p=0.028), of S. aureus isolation by blood culture (50% versus 0% in MTSS), and the higher mortality rate in NMTSS (22% versus 0% in MTSS). The tst and sea genes were less frequent in isolates causing NMTSS than in those causing MTSS (p<0.001 and 0.051, respectively). Higher mortality was significantly associated with the presence of the sed gene (p=0.041), but when considering NMTSS survivors and non-survivors, no clinical or bacteriological factors predictive of vital outcome were identified. Specific antitoxinic therapy was rarely prescribed, and never in fatal cases. Higher mortality was observed in NMTSS than in MTSS, and no definite factors could explain the higher severity of NMTSS. NMTSS would require more aggressive therapy, comprising systematic rapid wound debridement, antistaphylococcal agents, including an antitoxin antibiotics, and intravenous immunoglobulin.