The purpose of this chapter is to provide a brief history of the use of plasma, as well as to provide a review of currently available products, indications for usage, and benefits of transfusion. The Prospective Observational Multicenter Major Trauma Transfusion (PROMMTT) trial, an observational study from ten level-one trauma centers, aimed to define the principles of Damage Control Resuscitation (DCR) and a balanced transfusion strategy. The Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) trial was the first randomized controlled trial to address the question of transfusion ratios. Together these studies, along with the remainder of body of plasma literature, have led to current transfusion recommendations. The current cornerstones of therapy for the management of a trauma patient in hemorrhagic shock include early hemorrhage control, permissive hypotension, and damage control resuscitation. The American College of Surgeons’ Trauma Quality Improvement Program (TQIP) recommends a target balance between 1:1 and 1:2 for plasma to red blood cell ratio and one single donor apheresis or random donor platelet pool for each six units of RBC.