Polypharmacy (ie, the use of multiple medications and/or the administration of more medications than are clinically indicated, representing unnecessary drug use) is common among the elderly. The goal of this research was to provide a description of observational studies examining the epidemiology of polypharmacy and to review randomized controlled studies that have been published in the past 2 decades designed to reduce polypharmacy in older adults. Materials for this review were gathered from a search of the MEDLINE database (1986-June 2007) and International Pharmaceutical Abstracts (1986-June 2007) to identify articles in people aged >65 years. We used a combination of the following search terms: polypharmacy, multiple medications, polymedicine, elderly, geriatric, and aged. A manual search of the reference lists from identified articles and the authors' article files, book chapters, and recent reviews was conducted to identify additional articles. From these, the authors identified those studies that measured polypharmacy. The literature review found that polypharmacy continues to increase and is a known risk factor for important morbidity and mortality. There are few rigorously designed intervention studies that have been shown to reduce unnecessary polypharmacy in older adults. The literature review identified 5 articles, which are included here. All studies showed an improvement in polypharmacy. Many studies have found that various numbers of medications are associated with negative health outcomes, but more research is needed to further delineate the consequences associated with unnecessary drug use in elderly patients. Health care professionals should be aware of the risks and fully evaluate all medications at each patient visit to prevent polypharmacy from occurring.