Fluid administration is a key intervention in hemodynamic resuscitation. Timely expansion (or restoration) of plasma volume may prevent tissue hypoxia and help to preserve organ function. In septic shock in particular, delaying fluid resuscitation may be associated with mitochondrial dysfunction and may promote inflammation. Ideally, infused fluids should remain in the plasma for a prolonged period. Colloids remain in the intravascular space for longer periods than do crystalloids, although their hemodynamic effect is affected by the usual metabolism of colloid substances; leakage through the endothelium in conditions with increased permeability, such as sepsis; and/or external losses, such as with hemorrhage and burns. Albumin has pleiotropic physiological activities including antioxidant effects and positive effects on vessel wall integrity. Its administration facilitates achievement of a negative fluid balance in hypoalbuminemia and in conditions associated with edema. Fluid resuscitation with human albumin is less likely to cause nephrotoxicity than with artificial colloids, and albumin infusion has the potential to preserve renal function in critically ill patients. These properties may be of clinical relevance in circulatory shock, capillary leak, liver cirrhosis, and de-escalation after volume resuscitation. Sepsis is a candidate condition in which human albumin infusion to preserve renal function should be substantiated.