The injection of a sublethal bolus of E. coli into conseious swine produces an early increase in PAP and a decrease in LAP. This hemodynamic effect may be secondary to the pulmonary venous constriction seen in other species, or may relate to demonstrated multiple pulmonary microemboli. Hypoxemia developed in only four of 17 animals although all endotoxin-treated swine showed interstitial edema and elevated wet/dry weight rations with normal pulmonary surfactat. In addition, endotoxin-treated swine developed signs of disseminated intravascular coagulation, with renal cortical infarcts in 44%, and coronary arterial thrombi in 28% including one transmural myocardial infarction. This effect was observed in the absence of prolonged hypotension in swine and should provide a useful model for further study of the relationship of endotoxin to disseminated intravascular coagulation.