Preclinical fluid resucitation of multiply traumatised patients remains the subject of some controversy. There can be no doubt about the high risk of massive blood loss and subsequent centralisation with shock following a severe injury. Besides stopping the bleeding, fluid resucitation is the second mainstay of shock therapy. The aims of fluid resucitation are to increase the circulating volume in the vascular system and to increase the cardiac preload, but also to increase the total oxygen supply and thus to improve the microcirculation. As well as its intended effects, however, fluid resuscitation can have side effects. These include cardiac decompensation or interstitial oedema, especially when crystalloid solutions are infused. In the case of manifest or impending hypovolaemic shock, two large-caliber i.v. lines should be placed. In patients who are not showing signs of shock fluid resuscitation is not strictly necessary. If bleeding caused by trauma cannot be stopped at the scene, many experts recommend permissive hypotension (80–90 mmHg) and rapid transfer to a trauma centre. Crystalloid solutions should be used for fluid resucitation. It has not yet been possible to determine the relative value of small volume resuscitation, this topic is currently being researched.