Background Hemorrhagic shock (HS) often causes coagulopathy due, in part, to decreased coagulation proteins. This study assessed the efficacy of fresh frozen plasma (FFP) in preventing this coagulopathy following a canine model of HS designed to mimic bleeding with shock as seen in the emergency department followed by bleeding without shock as seen during operation for control of bleeding. Methods Twenty-two dogs had acute HS for 2 hours followed by resuscitation with red blood cells (RBC) plus lactated ringers (LR) or RBC and LR with FFP. After resuscitation, bleeding was continued for 1 hour while intravenous replacement of RBC and LR with or without FFP was provided. Baseline, postshock, postresuscitation, post-1 hour exchange, postoperative day one and day two measurements included coagulation Factors I, II, V, VII, VIII, and X, and the prothrombin (PT), partial thromboplastin (PTT), and thrombin times (TT). Results Baseline, postshock, and postresuscitation hemodynamic responses, coagulation factor levels, and coagulation times were similar for both groups. By contrast, the 1-hour postexchange factors were depleted in the LR dogs compared to the FFP dogs. This depletion correlated with prolonged PT, PTT, and TT in the LR dogs (mean 14, 35, and 8 seconds) compared to FFP dogs (9, 24, and 6 seconds). Conclusions Severe HS beyond one blood volume exceeds the interstitial stores of coagulation protein, thus necessitating FFP supplementation.