Although the incidence and prevalence of serious adverse drug reactions (ADRs) in the elderly cannot be accurately stated, published estimates appear to be unchanged since the earliest reports in the 1960s. Whereas heightened awareness of the problem may weigh in favour of a reduction in ADR frequency, the dramatic increase in the number and availability of therapeutic agents has undoubtedly contributed to the observed high proportion of drug-induced morbidity among acute geriatric hospital admissions. No single drug or drug class is of particular concern since none appears to cause serious morbidity out of proportion with its use. Although numerous studies have sought to identify risk factors for ADRs, the only truly independent predictor is the absolute number of concurrently used medications. However, other studies indicate that there is poor doctor-patient agreement regarding a patient's drug regimen, and interventions that aim to reduce the incidence of ADRs have failed to demonstrate a positive effect. Thus at present the most rational approach would appear to be to establish an accurate knowledge of the patients drug regimens: once this is known one can attempt to rationally minimise the number of medications without compromising therapeutic goals.