The use of intravenous (IV) fluids for volume resuscitation and fluid replacement in the surgical or critically ill patient has been studied and practiced for nearly 90 years. Four systematic reviews have pooled data from randomised controlled trials (RCTs) comparing isotonic crystalloids to colloids in clinically heterogeneous populations. Human albumin has received the most attention and controversy amongst IV fluids. Amongst patients with penetrating injuries requiring surgery, initial fluid resuscitation with hypertonic saline dextran (HSD), compared with isotonic crystalloids, appears to increase the survival rate to hospital discharge. A large number of RCTs have been conducted in the field of fluid therapy; however, most of them have been small and not powered to detect differences in clinical outcomes. The publication of the Saline versus Albumin Fluid Evaluation (SAFE) Study has demonstrated the feasibility of conducting large multicentre RCTs to answer questions on fluid therapy.