In order to determine whether acute hospitalization leads to changes in the medications used by the elderly after discharge, we studied the medications used at admission and discharge for 197 elderly subjects admitted to one hospital. We found that 40% of all admission medications were discontinued by discharge and 45% of all discharge medications were newly started during the hospitalization. Although the number of drugs used did not increase significantly from admission to discharge (4.50 to 4.80, P = .128), the number of narcotics, laxatives, and antibiotics increased significantly. For those elderly subjects admitted to the hospital taking less than the average number of medications, the overall use of medication increased from admission to discharge (2.89 to 3.75, P less than .0001). These "low users" were discharged on more benzodiazepines, narcotics, laxatives, antibiotics, and cardiac medications. Our data suggest that during hospitalization admission medications are discontinued and new medications are started in large numbers and that these changes are accompanied by a tendency towards the increased use of certain categories of medications. These changes may place the elderly patient at increased risk of polypharmacy and its complications.