Thrombomodulin (TM) is an important regulator of intravascular blood coagulation and inflammation. TM inhibits the procoagulant and proinflammatory activities of thrombin and promotes the thrombin-induced activation of protein C (PC) bound to the endothelial PC receptor (EPCR). Activated PC (APC) inactivates coagulation factors Va and VIIIa, thereby inhibiting blood clotting. Additionally, APC bound to EPCR exerts anti-inflammatory and cytoprotective effects on vascular endothelial cells. TM also protects cells in blood vessels from inflammation caused by pathogen-associated and damaged cell-associated molecules. Excessive anticoagulant, anti-inflammatory, and tissue regenerative effects in the TM-PC pathway are controlled by PC inhibitor. A recombinant TM drug (TMα), a soluble form of natural TM developed from the cloned human TM gene, has been evaluated for efficacy in many clinical trials and approved as a treatment for disseminated intravascular coagulation (DIC) caused by diseases such as sepsis, solid tumors, hematopoietic tumors, and trauma. It is currently widely used to treat DIC in Japan.