Diffuse alveolar hemorrhage (DAH) is a poorly understood complication of transplantation carrying a high mortality. Patients commonly deteriorate and require intensive care unit (ICU) admission. Treatment with high-dose steroids and aminocaproic acid (ACA) has been suggested. The current study examined 119 critically ill adult hematopoietic transplant patients treated for DAH. Patients were subdivided into low-, medium- and high-dose steroid groups with or without ACA. All groups had similar baseline characteristics and severity of illness scores. Primary objectives were 30, 60, 100 day, ICU and hospital mortality. Overall mortality (n=119) on day 100 was high at 85%. In the steroids and ACA cohort (n=82), there were no significant differences in 30, 60, 100, day, ICU and hospital mortality between the dosing groups. In the steroids only cohort (n=37), the low-dose steroid group had a lower ICU and hospital mortality (P=0.02). Adjunctive treatment with ACA did not produce differences in outcomes. In the multivariate analysis, medium- and high-dose steroids were associated with a higher ICU mortality (P=0.01) as compared with the low-dose group. Our data suggest that treatment strategies may need to be reanalyzed to avoid potentially unnecessary and potentially harmful therapies.