Despite successful management of early complications in polytraumatized patients and obvious reduction of early death, lethality in the late course of the disease--frequently as a result of multiple organ failure (MOF)--remains generally unaffected. Concerning the pathogenesis of sepsis and MOF, there is some evidence that a central role is played by endotoxin. A series of 32 patients with severe polytraumatic injury (Hannover Polytrauma Score > 20 points) comprised the study group. Endotoxin was measured hourly over the first 24 hours. The first measuring point was four hours after injury at the latest. Endotoxin levels were determined by a quantitative turbidimetric limulus assay. The Goris MOF score reached between the 8th and 10th day after injury was used for evaluation of the severity of MOF. Thirty of the 32 patients showed episodes of endotoxemia during the measuring period. There was a strong correlation between observed endotoxin peak concentrations, on the one hand, and outcome as well as positive predictive value (PPV) concerning development of MOF, on the other hand. If the peak concentration was greater than 10 pg/ml, the PPV reached 100%. No patient survived a peak concentration greater than 12 pg/ml. Endotoxemia during the early phase after polytraumatic injury is a frequent phenomenon. It appears to be possible that measurement of endotoxin peak concentration during the early phase gives some indication of the development of MOF and the outcome of these patients.