Can Free/Open Source Medical software also be called evidence-based medical software? Horst Herb at OSHCA 2002 spoke about the ethics, or lack thereof, of using black box (proprietary) software for making medical decisions. There would appear to be a number of parallels between evidence-based medicine and free/open source medical software. One would be the ability to examine decision making to its origins in open source clinical computing software. This currently isn’t possible with proprietary clinical computing software. Another, perhaps negative, parallel is the possibility of this effective reform being ignored by many practicing physicians.