This is a review article of the debated massive use of balance electrolyte solutions in the replacement of blood loss. We cannot directly apply the results and conclusions of American reviews on this subject as there are significant differences between USA and Finland in the use and availability of alternative fluids. Electrolyte solutions pass freely across the capillary membrane and are distributed in the extracellular compartment and as such poorly restore and maintain blood volume. In order to be effective they have to be infused in volumes trice the blood loss. Efficient protective mechanisms in the pulmonary capillary membranes prevent the appearance of pulmonary interstitial edema even when crystalloids are used in massive amounts. There is however significant water retention and edema in the periphery which results in impaired tissue oxygenation. The optimum anion composition of balanced electrolyte solutions is unsettled. In blood loss replacement electrolyte solutions without dextrose are preferred. The minimal amounts of potassium in balanced electrolyte solutions is of no practical value. Even though crystalloid solutions can be tolerated in massive amounts, marked blood loss is replaced more physiologically and effectively using natural or artificial colloids in iso-oncotic concentrations together with red cell concentrates and fresh blood.