And he said unto them, Ye will surely say unto me this proverb, Physician, heal thyself: whatsoever we have heard done in Capernaum, do also here in thy country.
Generally, this phrase is understood as a rhetorical metaphor referring to the expectancy of folks in Jesus' hometown for him to work miracles there like he had elsewhere.
For it to be used metaphorically, the chances are good that "heal thyself" was around well before it was documented in the Bible. I am guessing it originated in those cradles of Western medicine: Egypt or Greece.
This is, by the way, the first time I have vomited in my adult life. Before last night, I never understood why patients weren't able to fully describe the color and consistency of their vomit. Now I know! The first thing on your mind after the purge (besides old proverbs, of course) is "get rid of it!"