Soluble thrombomodulin is a promising therapeutic natural anticoagulant that is comparable to antithrombin, tissue factor pathway inhibitor and activated protein C. We conducted a multicenter, double-blind, randomized, parallel-group trial to compare the efficacy and safety of recombinant human soluble thrombomodulin (ART-123) to those of low-dose heparin for the treatment of disseminated intravascular coagulation (DIC) associated with hematologic malignancy or infection. DIC patients (n = 234) were assigned to receive ART-123 (0.06 mg kg(-1) for 30 min, once daily) or heparin sodium (8 U kg(-1) h(-1) for 24 h) for 6 days, using a double-dummy method. The primary efficacy endpoint was DIC resolution rate. The secondary endpoints included clinical course of bleeding symptoms and mortality rate at 28 days. DIC was resolved in 66.1% of the ART-123 group, as compared with 49.9% of the heparin group difference 16.2%; 95% confidence interval (CI) 3.3-29.1. Patients in the ART-123 group also showed more marked improvement in clinical course of bleeding symptoms (P = 0.0271). The incidence of bleeding-related adverse events up to 7 days after the start of infusion was lower in the ART-123 group than in the heparin group (43.1% vs. 56.5%, P = 0.0487). When compared with heparin therapy, ART-123 therapy more significantly improves DIC and alleviates bleeding symptoms in DIC patients.