Shock is a syndrome of inadequate tissue oxygenation due to reduced perfusion of organic sytems, organs and tissues, and consequent unsustainable aerobic metabolism. There are several classification of shock. For therapy, the most important one is the one that includes clinical presentation and pathophyisiology. That classification recognises four classes of shock: hypovolemic, cardiogenic, opstructive and distributive. The most common hypovolemic shock is hemorraghic shock. The most common cause of hemorraghic shock is trauma. The second most common cause is gastrointestinal bleeding. Severe bleeding is often found in thoracic cavity, abdomen, retroperitenoal and in large external wounds. The most casual signs of shock are: hypotension, tachycardia, oliguria, abnormal mental status and cold, clammy skin. Beside clinical presentation, in diagnostic of shock, very significant are laboratoy parameters and imaging methods. If bleeding is massive and ongoing, laboratory measurements can be inaccurate, then empiric therapy should take place. Hemmoraghic shock treatment includes stopping bleeding (most often with surgery), Intravenous fluid resuscitation with crystalloids or colloids, transfusion of red blood cells, transfusion of red blood cells with clotting factors and platelets. Massive transfusion is defined as the replacement by transfusion of 10 units of red cells in 24 hours, or five units over three hours. With massive transfusion, complications such as coagulopathy, hipotermia and metabolic complications can occur. Coagulopathies can occur with massive tissue damage and with diluton of clotting factors and platelets with crystaloids and colloids. Metabolic complications are metabolic alkalosis and hypocalcemia. Transfusion of more than three units of inadaquate warm blood could lead to hypotermia