In 2008, we saw the withdrawal of aprotinin from the US markets after preliminary results from a large, randomized clinical trial in Canada. This drug, a potent antifibrinolytic, was used primarily in complex and/or redo cardiac surgery as an adjunct to decrease postoperative bleeding and complications. The Canadian study raised questions previously brought up in similar studies—does aprotinin increase the risk of mortality and renal failure after cardiac surgery? Recently, a re-review of the Canadian data noted flaws in the study, as well as in the interpretation of the results. The present review revisits the aprotinin controversy.