Pyrrolizidine alkaloids induced hepatic sinusoidal obstruction syndrome (PA-HSOS) often occurs after consuming herbs or a dietary supplement containing the plant Tu-San-Qi. Limited data exists to identify patients with fatal outcomes for early interventions. We aimed to analyze the predictors for 3-month survival. We retrospectively enrolled PA-HSOS patients in 5 hospitals and extracted data from the onset of PA-HSOS to 36 months. Outcome measurements were 3-month and 36-month survival rates, baseline prognostic predictors for survival, and the effects of anticoagulant therapy. Among 49 enrollees, the median age was 60 and 49% male. At the onset of PA-HSOS, patients with Child-Turcotte-Pugh (CTP) class of A, B, or C were 8.2% (4/49), 42.8% (21/49) and 49.0% (24/49), respectively. None of them received a transjugular intrahepatic portosystemic shunt or a liver transplant. The 3-month and 36-month survival rates were 86% and 76%, respectively. Compared to the CTP class A or B, class C at baseline independently predicted lower survival rates at both 3 and 36 months. However, anticoagulation therapy treatment within the first 3 months independently predicted significantly higher survival rates at both time points. CTP class C and anticoagulant therapy were the independent predictors for short-term and long-term survival. Anticoagulant therapy could decrease mortality rate of CTP class C patients.The greatest benefit of anticoagulant evaluated by 3-month survival rate was in patients with CTP class C compared with those without treatment (93% vs 40%, P = .009). There were no bleeding complications reported in patients treated with the anticoagulant.