Hepatic sinusoidal obstruction syndrome (SOS), also called veno-occlusive disease (VOD), is a systemic endothelial disease that typically presents in the days or weeks after hematopoietic cell transplantation (HCT) with refractory thrombocytopenia, hepatomegaly, ascites, and jaundice, andit can rapidly progress to multiorgan dysfunctionand death. Rarely, SOS can arise after other causes of liver injury. A high index of suspicion is needed to diagnose hepatic SOS, and effective management is criticalfor reducing the associated morbidity and mortality.