The present study describes the effect of plasma exchange or whole blood exchange (PEBE) on the survival rate among patients with fulminant meningococcal sepsis and on the level of circulating endotoxin. Since 1989 all patients with meningococcal disease and hypotension who were admitted to our intensive care unit were treated with PEBE. Results for our patients were compared with those for a historical control group conventionally treated between 1984 and 1989 (n=10; mortality rate, 60%); the expected mortality rate, which was based on the Niklasson prognostic score and was calculated for seven patients in this control group, was 73%. A total of 15 patients were treated with PEBE, three (20%) of whom died, whereas the prognostic score (calculated for 14 patients) for this group was 62%. In two of the fatal cases, PEBE was started after a delay of ⩾40 hours. In the remaining 13 patients, PEBE was started within 5–30 hours after the first hospital admission. The mortality rate among this group was 8% (one of 13 patients); this rate was significantly different from that among the control group (P= .025). For seven patients treated with PEBE, plasma endotoxin concentrations were sequentially measured. The overall half-life (± SEM) of endotoxin was 181 ± 18 minutes. This is approximately the same as reported values for patients who were not treated with PEBE. It is concluded that early initiation of PEBE may improve the rate of survival among patients with meningococcal infection and hypotension but that the mechanism of the beneficial effect is most likely not based on the elimination of endotoxin.