BACKGROUND: Reports of clinical trials usually emphasize efficacy results, especially when results are statistically significant. Poor safety reporting can lead to misinterpretation and inadequate conclusions about the interventions assessed. Our aim was to describe the reporting of harm-related results from randomized controlled trials (RCTs). METHODS: We searched the MEDLINE database for reports of RCTs published from January 1, 2006, through January 1, 2007, in 6 general medical journals with a high impact factor. Data were extracted by use of a standardized form to appraise the presentation of safety results in text and tables. RESULTS: Adverse events were mentioned in 88.7% of the 133 reports. No information on severe adverse events and withdrawal of patients owing to an adverse event was given in 27.1% and 47.4% of articles, respectively. Restrictions in the reporting of harm-related data were noted in 43 articles (32.3%) with a description of the most common adverse events only (n = 17), severe adverse events only (n = 16), statistically significant events only (n = 5), and a combination of restrictions (n = 5). The population considered for safety analysis was clearly reported in 65.6% of articles. CONCLUSION: Our review reveals important heterogeneity and variability in the reporting of harm-related results in publications of RCTs.