The first reference to a healer as a quack goes back into the sixteenth century.
In those days it was common for dubious medicine men to travel from town to town dispensing their miracle cures from the back of a horse-drawn wagon.
The quack refers to the meaningless sound of a duck, which had the same validity as the claims made by the medicine men that their salves or ointments had healing powers.
Today’s quacks still dispense bad medicine.
The word “quack” comes from from the archaic Dutch word “quacksalver,” or “kwakzalver” in contemporary Dutch.
It means “boaster who applies a salve.”