Performance support systems that provide decision support and encourage quality improvement historically focus on physicians as the expert to the exclusion of an active role for patients. This paper outlines an argument for the development of a collaborative expert system in the acute care setting that emphasizes a key role for patients. Patients are not just seekers of information; they remain capable of sharing and integrating their knowledge and expertise actively in an electronically-supported care process. Collaborative use of information technology emerges as a novel variation of consumer informatics. I will define specific domains of expertise for patients and place the proposed collaborative expert system within the framework of Wagner's view of idealized collaborative care for chronic illness. Basic architecture for a patient-inclusive system is proposed with additional detail provided for a patient-level interface targeting pediatric asthma. The benefits of the electronically-supported collaboration include the activation of patients in the information-sharing process, enhanced decision support, a patient-focused needs assessment, and improved communication and partnership between patients and providers.