OSCAR (Open Source Clinical Application and Resource) from McMaster University is a web-based EMR (electronic medical record) system developed for academic primary care clinics yet suitable in specialty and non-teaching practices. It integrates with Drugref to provide Canadian pharmacopea.
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iPath is providing a free and open platform for "case based collaboration", especially designed for medical applications (telemedicine, etc). The iPath-Server package provides a sort of medical BBS to discuss/consult cases online. Additional modules are available.