To “get a clean bill of health” is to be told by some authoritative source, generally a doctor, that one is perfectly healthy. The phrase is sometimes used figuratively to indicate that a person or organization has been found free of any sort of irregularity: “After looking into her financial background, the Senate gave the nominee a clean bill of health.”
clean bill of health
A report confirming the absence of fault or guilt in a person or thing, as in Jeff checked every component and gave the computer a clean bill of health, or He had a foolproof alibi so the police had to give him a clean bill of health. This term comes from a 17th-century practice of requiring ships to produce a medical document (bill) attesting to the absence of infectious disease on board before landing.