Until recently, the effects of adverse drug events in Canada had not been characterized, but it is now evident that significant morbidity, mortality, and economic impact can be related to adverse drug events. More specifically, it has been estimated that as many as 25% of general medicine admissions and 12% of visits by adults to the emergency depart ment in this country are directly related to adverse drug events, of which 70% are deemed preventable. 4,5 In the Canadian Adverse Events Study, 7.5% of all inpatients experienced an adverse event during their hospital stay and nearly 24% of the events were related to drug or fluid administration. 6 Finally, in another study, 23% of patients experienced an adverse event within 30 days after hospital discharge, 72% of the events were associated with drugs, and 50% of the events were preventable. 7