We first identified a list of the most commonly used 179 drugs in 2008 based on the Agency for Healthcare Research and Quality compiled Medical Expenditures Survey. We then used Micro-Medex, a commercial drug information service, to find a list of key publications describing ADEs for these drugs. Next, we obtained the text for the majority of letters to the editor published in The Lancet (6558 from 1967 to date; 82% of total) and The New England Journal of Medicine (3524 from 1966 to date; 75% of total). We restricted the letters to those that had the MeSH term 'adverse effect' in the indexing data. We also eliminated the letters with label 'Comment' to avoid searching letters specifically referencing a previously published paper in each journal, respectively. The resulting dataset contained 2166 letters for The Lancet and 1449 for The New England Journal of Medicine.