Use of red cells for transfusion in a tertiary care hospital has been studied over a 7-year period from 1990-1991 to 1996-1997. In this time, red-cell use has declined by 18% while new patients or admissions to programmes in oncology, trauma or cardiac bypass surgery have increased by 57%, 66% and 73%, respectively. This reduction in red-cell transfusion has been achieved by a combination of less patients (proportionately) receiving red cells and less red cells being transfused to individual recipients. When the trends are analysed for red-cell use in four elective surgical procedures there is a significant reduction in both the proportion of patients transfused and the mean number of units used per patient undergoing the procedure. Autologous presurgical blood deposit met about 45% of the blood requirement for those four procedures. A similar decreasing trend in units per patient and proportion of patients transfused red cells was seen for 'first-time' coronary artery bypass surgery. The question arises as to how far this trend may go before adverse effects of undertransfusion become apparent.