Increasing data from a few sites demonstrate that information technologies can improve physician decision making and clinical effectiveness. For example, computer-based physician order entry systems, automated laboratory alert systems, and artificial neural networks have demonstrated significant reductions in medical errors. In addition, Internet services to disseminate new knowledge and safety alerts to physicians more rationally and effectively are rapidly developing, and telemedicine to improve rural access to specialty services is undergoing substantial growth. However, even technologies demonstrated to yield beneficial effects have not yet achieved widespread adoption, though the pace of change appears to be increasing as the Internet takes hold. Scientific evaluation of many technologies is also lacking, and the dangers of some of these technologies may be underappreciated. Research on the effects of specific technologies should be a priority. Policies should be developed to press information technology companies, such as pharmaceutical and medical device manufacturers, to recognize the importance of clinical evaluation. Research could also analyze the characteristics of effective technologies and of physicians and organizations who implement these technologies effectively.