This review examines the science and methodology of blood conservation in modern anaesthetic and surgical practice. Blood transfusion is associated with increased morbidity and mortality in all surgical patients, and the reduction or even elimination of transfusion has been and continues to be the subject of much research. Blood substitutes, despite extensive investigation, have not been proved successful in trials to date, and none have entered clinical practice. Pharmacological treatments include antifibrinolytic drugs (although aprotinin is no longer in clinical use), recombinant factor VIIa, desmopressin, erythropoietin and topical haemostatic agents, and the role of each of these is discussed. Autologous blood transfusion has recently fallen in popularity; however, cell salvage is almost ubiquitous in its use throughout Europe. Anaesthetic and surgical techniques may also be refined to improve blood conservation. Blood transfusion guidelines and protocols are strongly recommended, and repetitive audit and education are instrumental in reducing blood transfusion.