The purpose of the study was to explore drug use of elderly incontinent female nursing home residents, to identify potential drug--drug interactions, and to identify the number and categories of drugs taken having the potential to cause urinary incontinence. The medication administration records of 84 female residents were examined. The drugs were categorized by therapeutic classification as designated by the American Hospital Formulary Service. Potential drug--drug interactions were identified using The Hansten Drug Interaction Knowledge Base Program, a microcomputer version of Hansten's (1985) book Drug Interactions. Data were computer-coded and analysed using the Statistical Analysis System (SAS). A total of 454 drugs was taken by the 84 subjects, with an overall average of 5.40 drugs per person. The most frequently taken drugs were gastrointestinal drugs, central nervous system agents, electrolytic, caloric, and water balance drugs, and cardiovascular drugs. Fifty per cent (n = 42) of the subjects were identified as having 119 potential drug-drug interactions. Seventy per cent (n = 59) of the subjects were taking a drug having the potential to cause urinary incontinence. Suggestions for future research are presented.