At the 42nd Annual Meeting of the European Society for Blood and Marrow Transplantation (EBMT), held in Valencia, Spain, EBMT 2016 President Mohamad Mohty, MD, PhD, from Saint-Antoine Hospital, Paris, France, talks about veno-occlusive disease (VOD), a rare but serious complication that can occur after allogeneic transplantation. Severe VOD can be fatal in up to 80% of patients. The approval of the novel polydisperse oligonucleotide defibrotide for the treatment of VOD treatment rejuvenated this field, with EBMT 2016 discussions focusing on the criteria for the diagnosis and grading of the severity of this complication.