In this week's BMJ, Ian Roberts, Richard Smith, and Stephen Evans describe the worrying story of Dr Julio Cruz.1 Cruz, a previously highly regarded medical researcher and clinician, committed suicide two years ago. Three of his publications about the use of high dose mannitol in head injury have recently been called into question. Furthermore, his coauthors and the editors of the journals in which the three papers were first published have failed to respond adequately to concerns raised about the integrity of the data in these papers.

These events have several important consequences. Many doctors base key treatment decisions on the results of published randomised trials. If some or all of Cruz's data on high dose mannitol are false, then doctors will be providing their critically ill patients with uncertain and possibly harmful treatment. In doing so, those doctors will also deny their patients other treatments that are based on reliable evidence.

The failure to retract unsound data also has long term consequences as the data become integrated into reviews, meta-analyses, and guidelines. These syntheses of primary research affect the practice of clinicians worldwide, and in turn affect even larger numbers of patients. In addition, unless and until the veracity of Cruz's data is formally proved or disproved, there is a risk that further research will …