The copious publications of high-profile German cardiologist Bodo-Eckehard Strauer — who has long claimed that stem cells derived from bone-marrow cells can repair damage in diseased hearts — have come under new attack.

Strauer, who retired from the University of Düsseldorf in 2009, has been a controversial figure in Germany since he first claimed clinical success with the approach in 2001. Many stem-cell scientists have been openly sceptical of his claims, which have been reported enthusiastically in the media.

An article published this week in the International Journal of Cardiology dissects 48 of the papers from his group and exposes a series of problems, including arithmetic errors in the presentation of statistics and identical results in papers presenting different numbers of patients. The authors also searched systematically in all of the papers for discrepant information — pairs of statements that could not both be true.