In a study involving 1499 patients in a family office, prescription data obtained from a computerized record system (COSTAR) were analyzed to determine the drug interaction rate. While prior studies have adequately determined that drug interactions occur frequently in most medical offices this paper presents a methodology for performing such analyses in a very short period of time. By using a computer at all stages, the analysis was computed in less than four weeks and with more accuracy than would otherwise be possible. In addition to the demonstration of a method, the results of our analysis are also of interest. Overall 138 (9.2%) of the study patients were prescribed drugs with known interaction potential and among this group, 123 (72%) had interactions considered to be of "moderate" clinical significance and 36 (17%) had interactions considered to be of "major" significance.