Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) can be fatal, and abnormalities in the coagulation system of patients with AE-IPF have been reported. Recombinant human soluble thrombomodulin (rhTM) forms a complex with thrombin to inactivate coagulation. It also inhibits high-mobility group box protein 1 (HMGB-1), which results in the suppression of inflammation.