Google launched Google Health back in February 2008. Today, Google is integrating Google Health content into the search results via the classic OneBox section of the page. You should be able to see the Google Health OneBox for medical related searches, such as for [asthma] or [diabetes].
Google provides a quick definition of the condition and then gives you a link to either Google Health, Mayo Clinic, Medline Plus or WebMD. Note, not all of these links will be available for all health-related queries.
Search Engine Land by Barry Schwartz, 08/27/2009