Randomized controlled trials have been regarded as the best way of answering scientific queries in clinical medicine, but the practical difficulties of conducting them often leave their results open to widely varying interpretation. It may be time to look at alternative forms of evidence in critically ill patients.4 Sir Karl Popper wrote, “If you insist on strict proof (or strict disproof) in the empirical sciences, you will never benefit from experience, and never learn from it how wrong you are.”5 My own experience in managing adult patients receiving ECMO for refractory respiratory failure caused by proven 2009 influenza A(H1N1) is limited. I have only attended to four such patients, two of whom also had concurrent circulatory collapse. Happily, all four patients completely recovered. Surely, it is time to move beyond the erroneous supposition that ECMO does little but harm. Stop calling for more efficacy trials and focus instead on when, how, and in whom we can optimally use the technique.