Previous research has shown that there is a high error rate associated with medication use, resulting in significant patient morbidity and mortality, as well as increasing health care costs. Analysis of available Australian data on adverse drug events shows that incident monitoring and retrospective medical record review provide different, but complementary 'windows' into the errors that occur. While retrospective medical record review provides information on the frequency of specific adverse drug events, incident monitoring gives an insight into the contributing factors. From this information, priorities can be set and preventative strategies can be developed.