The blood ordering practices for acute upper gastrointestinal bleeding were assessed in 162 consecutive patients presenting with haematemesis admitted via the Accident and Emergency Centre. The patients were classified according to their estimated blood loss and haemoglobin level at the time of admission, and the amounts of blood ordered and given in the next 24 h were determined. The crossmatch: transfusion (CT) ratio was very high in one group (14.9), although the overall ratio of 2.4 was acceptable. There were marked variations in the ordering pattern of different medical officers, possibly because of the absence of clear guidelines. From the data obtained, a set of guidelines for ordering blood in this clinical condition was developed. It was estimated that if these guidelines had been used, there would have been a reduction of one-third of all units crossmatched, and that the overall CT ratio would have been reduced to 1.6.