Systemic inflammatory response syndrome (SIRS) is characterized by body temperature abnormalities, tachypnea or hyperventilation, tachycardia, and leukocytosis or leukopenia. Although it is typically associated with a serious infection and referred to as sepsis, SIRS can stem from noninfectious causes, as well. We report the cases of four patients with toxic serum levels of salicylate (33.5 to 67.6 mg/dL) and SIRS, and we discuss mechanisms responsible for SIRS. Our patients showed temperature disturbances (35.5 degrees C to 39.8 degrees C), noncardiogenic pulmonary edema, and mixed acid base disturbances. Other abnormalities included coagulopathy (disseminated intravascular coagulation), encephalopathy, and hypotension. All four patients recovered from SIRS, probably due to early recognition and treatment; only one patient did not survive the hospitalization. Chronic salicylate toxicity should be considered as a cause of SIRS in the absence of a source of infection, since survival appears to be dependent on prompt diagnosis and management.