There is some preliminary evidence, that veno-occlusive disease prophylaxis with defibrotide (DF) may also have a role in decreasing risk of acute graft-versus-host disease (aGvHD) by preventing tissue damage. In this study, we aimed to investigate the role of DF prophylaxis on the development of aGvHD at D + 180. One hundred ninety-five consecutive adult patients receiving allogeneic HCT were retrospectively evaluated in 3 groups: no DF, DF/post-Ha (DF D +1 to D + 14) and DF/pre-HCT (DF for 14 days concurrently with conditioning). The total (p: 0.057) and grades III/IV (p: 0.051) aGvHD rates at D + 180 were 46.5%, 40%, 25.5% and 15.5%, 11.2%, 0% in patients on no DF, DF/post-HCT and DF/pre-HCT. DF may have a role in decreasing incidence and severity of aGvHD, especially if used concurrently with conditioning regimen. (c) 2016 Elsevier Ltd. All rights reserved.