AIM Adverse drug reactions (ADRs) are a major burden in health care, regularly leading to hospital admission, morbidity or death. Women tend to have a higher risk of adverse drug reactions with a 1.5 to 1.7-fold greater risk than men. Our primary aim was to study differences in ADR-related hospitalizations between the sexes.METHODS We conducted a nationwide study of all ADR-related hospitalizations in the period between 2000 and 2005 in the Netherlands, which were selected from all 9 287 162 hospital admissions in this period. ADR-drug group combinations with at least 50 admissions in one of the sexes were selected. Relative risks and confidence intervals were calculated with respect to total admissions and total prescriptions with men as reference.RESULTS In total, 0.41% of the 4 236 368 admissions in men (95% CI 0.40, 0.42%) and 0.47% of the 5