Citing the fact that nearly 1% of search queries are health-related, Google is bringing its own version of a symptom-checker into search results.
When it rolls out, Google symptom search will cull “high-quality medical information” from the Knowledge Graph to give searchers a reasonable guesstimation as to what their ailment may be. Google worked with both Harvard & the Mayo Clinic on a representative sample of queries to help ensure accuracy.
Though Google does already pull some health-related search results into Featured Snippets currently, this data does not come from Knowledge Graph.
Google is likely adding symptom search as a user-experience boost, rather than any immediate profit advantage. It stands to reason, however, that Google always benefits from keeping users on its own sites (rather then having them leave to go elsewhere).
Google symptom search will be limited to English-speakers on mobile devices in the US to start. The list of symptoms covered will also be sparse in the beginning, with both expanding over time.
As with any online medical resource, nothing should be considered a replacement for an actual doctor’s advice.