Endotoxin plays an important role in the pathogenesis of septicaemia by activation of cellular and plasmatic systems. This study was performed to investigate the effects of infusion of endotoxin in rabbits by measuring the activation of cellular and plasma systems. Endotoxin was infused at a rate of 1 mg/kg body wt for 10 min, which caused death of all rabbits within 72 h. Endotoxin induced early leukopenia and thrombopenia, increased plasma levels of beta-glucuronidase and leukotriene B4 (LTB4), and decreased complement total hemolytic activity (CH50) and tissue plasminogen activator (t-PA) activity. These observations correlate with the cellular and plasma changes that have been documented in severely ill endotoxemic patients. Therefore, we conclude that this endotoxin model in rabbits is a valuable tool for investigation of pathophysiology and treatment of endotoxic shock.