Nafamostat mesilate (NM), a synthetic serine protease inhibitor, has anticoagulant and anti-inflammatory properties. Nafamostat is approved and marketed in Japan. It relieves symptoms such as pain due to inflammation of the spleen. It improves visceral disorders and bleeding tendency caused by blood clotting tendency in the vessels. It prevents coagulation in the blood circuit during hemodialysis. It is usually used to improve acute symptoms of pancreatitis (acute pancreatitis, acute exacerbation phase of chronic pancreatitis, post-operative acute pancreatitis, acute pancreatitis after pancreatography, traumatic pancreatitis) and to prevent disseminated intravascular coagulation (DIC) and clotting of perfusing blood in extracorporeal blood circuit. Nafamostat mesilate significantly inhibits the release of platelet beta-thromboglobulin (beta TG) at 60 and 120 min. Nafamostat mesilate (NM) prevents any significant release of neutrophil elastase; at 120 min, plasma elastase-alpha 1-antitrypsin complex is 0.16 mg/mL in the NM group and 1.24 mg/mL in the control group. Nafamostat mesilate completely inhibits formation of complexes of C1 inhibitor with kallikrein and FXIIa.