The Compendium of Caraka 1.11.50

1.11.50

trividhā bhiṣaja iti
bhiṣakchadmacarāḥ santi santyeke siddhasādhitāḥ /
santi vaidyaguṇairyuktāstrividhā bhiṣajo bhuvi //

"Three types of physicians":
There are those who walk in the guise of physicians, there are those who are accomplished by association with the accomplished,
and there are those endowed with the qualities of a physician: three types of physicians are on earth.