72% of US internet users said they have looked online for health information in the past 12 months, mostly to search for a specific disease or medical problem (55%) or a certain medical treatment or procedure (43%), according to [pdf] results from a Pew Internet & American Life Project survey. Among these online health-seekers (who represent an estimated 59% of the total US population), 77% started at a search engine the last time they went online to look for health information, while 13% went to a site that specializes in health information.

via 7 in 10 US Internet Users Go Online for Health Info; Most Start With Search.