In autologous and allogeneic hematopoietic SCT (HSCT) neutropenia may be associated with severe infection. Immunodeficiency associated with GVHD and its treatment in allogeneic HSCT is also a risk for severe infection. In both periods, patients may develop severe sepsis with organ failure. To gain insights into treatment possibilities, HISTORY, a multicenter retrospective study reviewed HSCT patient records on mortality, organ dysfunction, platelet count and bleeding events. All transplantation records from 16 European centers were reviewed for 1.5 years. Of 2092 patients screened, 160 were documented for HSCT with respiratory and/or cardiovascular organ dysfunction because of sepsis and/or GVHD. Mortality was 53.1% at 28 days and 65.6% at 100 days. HSCT patients with sepsis and organ dysfunction are at highest risk of death (49.5%). Death from refractory septic shock was 15.2%, and it was 20% from respiratory failure and 64.7% from sepsis. Fewer than 3% of HSCT patients died from bleeding complications; however, individuals at increased risk of bleeding were excluded. Despite low platelet counts, an increased risk of bleeding could be established only if thrombocytopenia dropped below 13 x 10(9)/l. Thus, there might be a therapeutic window for treatment strategies for severe sepsis in HSCT, such as drotrecogin alpha (activated).