Alpha 2-antiplasmin （or α2-antiplasmin or plasmin inhibitor） is a serine protease inhibitor （serpin） responsible for inactivating plasmin. Plasmin is an important enzyme that participates in fibrinolysis and degradation of various other proteins. Very few cases （<20） of A2AP deficiency have been described. As plasmin degrades blood clots, impaired inhibition of plasmin leads to a bleeding tendency, which was severe in the cases reported. In liver cirrhosis, there is decreased production of alpha 2-antiplasmin, leading to decreased inactivation of plasmin and an increase in fibrinolysis. This is associated with an increase risk of bleeding in liver disease.