AIMS: To examine how countries differ in attitudes to adverse drug reactions by examining published scientific papers. METHODS: We searched Ovid EMBASE for publications indexed by the category "therapeutic agents", and the subcategory "adverse effects", by country for 43 countries. RESULTS: We counted 1 810 202 papers world-wide regarding therapeutic agents during 14 years, of which 195 154 (10.8%) were included in the adverse effects subcategory. There were substantial differences between countries, not explained by population, economic variation, overall publication rate on therapeutic agents, or the presence of large indigenous pharmaceutical companies. CONCLUSIONS: Many local cultural factors influence the ratio of papers on adverse reactions to all drug effects, so it may be difficult to improve their recognition and reporting by international efforts.