ObjectiveTo determine if histamine release occurs in clinical sepsis.DesignProspective, controlled, clinical study.SettingInterdisciplinary intensive care unit and trauma ward.PatientsSepsis was confirmed in 20 patients (test group) by the criteria of the Veterans Administration Systemic Sepsis Cooperative Study Group (1987) and was verified by positive blood culture. In addition, patients were scored by the Elebute and Stoner Sepsis Score (1983), as modified by Dionigi et al (1985). A concomitant control group consisted of 20 postoperative patients with non-life-threatening trauma to the extremities and without signs of local or systemic infection.InterventionsObservational study. Blood samples were collected for determination of plasma histamine concentrations in both groups at the time of study entry and on five succeeding days.Measurements and Main Results1 ng/mL) died.ConclusionIncreased histamine concentrations were shown to be causally associated (contributory determinant) with sepsis.(Crit Care Med 1996; 24:1670-1677)