Trauma favors the development of adult respiratory distress syndrome (ARDS). Adherence of polymorphonuclear leukocytes (PMN) to endothelial cells (EC) with subsequent EC damage by the respiratory burst products and proteases of the PMN is thought to be one of the basic mechanisms in the pathogenesis of ARDS. Recent studies have shown that there might also be PMN-independent mechanisms of EC damage. It would speak for PMN-independent EC damage if in the state of risk for this damage factors were found which decrease PMN activity or if EC damage appeared without PMN. Because in trauma and sepsis pathologic coagulation with high levels of fibrinogen degradation products (FDP) is often diagnosed, we investigated whether FDP-D and FDP-E might influence PMN adherence to EC. We also investigated whether serum of traumatized patients might provoke EC damage in a PMN-independent system in vitro. To achieve this we evaluated the viability of EC using a fluorescence staining method. We found that both FDP-D and FDP-E decreased PMN adherence to human EC significantly (p < 0.01) at a concentration of 50 µg/ml. Furthermore we found that EC membrane integrity can be disturbed by serum of trauma patients. These results suggest that in trauma also PMN-independent mechanisms are important for EC damage