Multiple pathology, a common phenomenon among the elderly, fosters the practice of multiple drug therapy which in turn is particularly hazardous for this age grouping. The total drug exposure of two typical elderly persons, one institutionalized and one living at home, were analyzed. Potentially harmful drug interactions were discerned in both cases. The findings suggest that health professionals, policy makers, and others who work with the elderly should take into account their total drug exposure (prescription, over-the-counter, social — alcohol, nicotine and caffeine) with special reference to iatrogenic and self-medicated hazards.