Despite the proliferation of computer-based resources for patients, usefulness has been limited to date. Already, 17,000 biomedical Internet sites exist, and patients are increasingly finding support and knowledge on the Internet, but the accuracy of the information found is highly variable and difficult for patients to assess. Patients have also found value in electronic communication with physicians, although relatively few physicians routinely use email to communicate with patients on a regular basis. Nonetheless, patient-focused information technologies potentially will have profound effects on medical care. With advancing sophistication of technology, patients will increasingly be able to compare and choose doctors using the Internet and to access information that allows them to monitor and regulate the quality of their own care. Further, technologies will likely be developed to allow patients to increasingly manage their own care -- whether they are patients with chronic illnesses such as diabetes or congestive heart failure who use customized software to adjust drug dosages and other treatments or patients with such common illnesses as headache or gastrointestinal infection who access self-management programs that may even write prescriptions for them. Thoughtful analysis and policy development will be critical for ensuring that the benefits are maximized and potential harm minimized. Specific areas include assessing the effects on outcomes and the characteristics of patients and technologies that succeed with self-management, and developing policies regarding liability for Web-based medical transactions and the privacy of information provided to physicians by email and via interactive Web sites.