Sclerotherapy of bleeding esophageal varices in liver cirrhotics is a common procedure, but little is known about the possible entry of sclerosants into the systemic circulation. We injected a mixture of thrombin, sodium tetradecyl, and cefazolin and studied the effect of this sclerosant on selected hemostasis parameters. Twenty-four patients with liver cirrhosis (Child's Classification C) were studied 29 times. Blood samples were drawn before and immediately after the injection of the sclerosant. In seven patients we collected a sample 30 minutes and 24 hours after treatment. Before injection, almost all patients had elevated D-dimer, t-PA and PAI-1 levels. Fibrinogen, antithrombin, alpha-2 antiplasmin, and protein C were decreased. Only thrombin/antithrombin III complex (TAT) levels were within normal ranges. Immediately after the injection, TAT, D-dimer, and t-PA levels rose significantly (P less than 0.001, P less than 0.01, P less than 0.001), PAI-1 and PC levels decreased (P less than 0.01), while antithrombin, alpha-2 antiplasmin, and fibrinogen concentrations were unchanged. TAT and D-dimer levels were still elevated after 24 hours (P less than 0.05). These data indicate that thrombin entered the systemic circulation (elevated TAT) and that the hemostasis system was briefly systemically activated (elevated D-dimer). In spite of these changes in the hemostasis system, clinically there were no detectable thrombotic or hemorrhagic complications.