Background Perioperative fluid therapy is always the subject of active controversy. Many clinical trials investigating the effects of fluid administration on outcome in surgical patients have reported controversial results. Purpose Reviewing the evidence behind current standard fluid therapy and analyzing the different trials examining the effects of fluid therapy on postoperative outcome. Content Fluids should be administered in the perioperative period through a goal-directed approach taking into account patients characteristics and surgical-related events, and not through a fluid therapy formula. The type of fluid to be administered should depend on the specific space that needs to be restored and on the pharmacokinetic properties of the different solutions. Trend Further studies must focus on specific patients’ population who may benefit from a particular kind of fluid, the timing of fluid administration, and on the improvement of monitoring measures to recognize volume deficits and to guide fluid therapy.