A retrospective analysis of 7 patients with streptococcal toxic shock revealed isolated prolongation of the activated partial thromboplastin time, which returned to normal during recovery. Levels of factor XII were reduced in 2 patients who had single factor assays performed, consistent with activation of the kallikrein-kinin system. We speculate that bradykinin release following activation of the kallikrein-kinin system in streptococcal toxic shock may underlie the features of pain, capillary leaking, and severe hypotension characteristic of this syndrome.