Veno-occlusive disease (VOD) of the liver is currently known as potentialy severe complication of stem cell transplantation. The pathogenesis of VOD is characterized by toxic disorder of sinusoidal endothelial cells and this is why the new term of sinusoidal obstruction syndrome has recently emerged. Diagnosis of this disorder remains to be mainly based on clinical criteria, with some contribution of plasminogen activator inhibitor-1 plasma levels. Preventive effect is better proved for ursodiol than for low-dose heparin. Treatment of VOD has been disappointing until recently, when a single-stranded polydeoxyribonucleotide with fibrinolytic properties, defibrotide, becomes promising for both therapy and prevention.

        Key words: veno-occlusive disease, sinusoidal obstruction syndrome, stem cell transplantation, defibrotide