In 42 patients with septic shock, 29 of whom underwent substitution with antithrombin III concentrate and fresh frozen plasma for coagulation disorders, the proteinase-inhibitor complexes thrombin-antithrombin III and neutrophil elastase-alpha 1 proteinase inhibitor, were elevated on admission. On admission, the elastase complex was significantly higher in the patients receiving substitution (p = 0.0039), but at the endpoint it was higher in the non-survivors (p = 0.0040). The elastase decrease was confined to the substitution group with the thrombin complex decreasing in both groups. Initially the thrombin complex correlated with prothrombin times and factor XIII, while the elastase complex correlated with creatinine, thrombocyte count and prothrombin times in the late stages. Hemostatic disturbance, thrombin generation and neutrophil elastase release were favorably influenced by substitution. Furthermore, in this uncontrolled pilot study, the survival rate was higher in the treated (16 of 29) than in the untreated (1 of 13) patients, although the treated patients initially had pronounced hemostatic disturbances.