Reason: We have received confirmation from Professor Anders Ekbom, who chairs the investigating commission appointed by the University of Oslo and Rikshospitalet, that the paper published by Jon Sudbø and colleagues in The Lancet contains fabricated data. This information supersedes our earlier expression of concern (R. Horton, Expression of concern: non-steroidal anti-inflammatory drugs and the risk of oral cancer, Lancet 367 (2006), p. 196; doi:10.1016/S0140-6736(06)68014-8) and we now retract this article in full.