[Ads-l] Adage Origin: Quacks Are the Greatest Liars in the World, Except Their Patients

[ADSGarson O'Toole]

Charlatans who provide fraudulent medical advice and dubious nostrums
have afflicted humankind for centuries. Misguided patients often boost
these deceivers the most. Here are two versions of a pertinent saying:

(1) There are no greater liars than quacks, except for their patients.
(2) Quacks are the greatest liars in the world, except their patients.

This saying has been attributed to U.S. statesman Benjamin Franklin,
U.S. physician Benjamin Rush, and Scottish physician David Pitcairn. I
received a request to investigate.

The earliest match I found occurred in a diary written by Benjamin
Rush. The entry dated September 22, 1788, described a conversation
about quacks between Benjamin Franklin and Rush. The word "liars" was
spelled "lyers" in the following excerpt:

[Begin excerpt]
Waited upon Dr. Franklin with Doctor Thibou, of Antigua. The Dr. said
few but quacks ever made money by physic, & that no bill drawn upon
the credulity of the people of London by quacks, was ever protested.
He ascribed the success of quacks partly to patients extolling the
efficacy of the remedies they took from them, rather than confess
their ignorance & credulity, hence it was justly said, "quacks were
the greatest lyers in the world, except their patients."
[End excerpt]

Rush's 1788 diary entry appeared in "The Pennsylvania Magazine of
History and Biography" in 1905 within an article titled "Excerpts from
the Papers of Dr. Benjamin Rush". I believe this diary entry is
credible; however, I have not yet seen scans of the diary entry.

The passage is ambiguous, but it seems that the saying was spoken by
Benjamin Franklin to Rush. The prefatory phrase "it was justly said"
signaled that the attribution was anonymous.

Here is a link to the Quote Investigator article:
https://quoteinvestigator.com/2026/09/09/quacks-liars/

Feedback welcome
Garson O'Toole

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