Traditionally, a transfusion trigger of 100 g/L has been recommended in the postoperative period, especially in older patients and in those with serious comorbidities. In the Transfusion Requirements in Critical Care trial, a much lower transfusion threshold (70 g/L) was adopted in the group of patients in whom transfusions were restricted. This prospective randomized trial that included 838 patients, is, to this day, the most important in the field and generated unexpected results. Serious morbidity (cardiac and respiratory in particular) and mortality were not increased by the adoption of a low transfusion trigger while the number of transfusions was decreased significantly.