Why do we take something uncertain “with a grain of salt”? The answer involves a universal antidote to poison, Bible commentary, and some questionable photos of Ireland.
To take something with a grain of salt means to understand that something may not be completely accurate, to interpret something skeptically because it may be unverified or uncertain. For example, if you were relating an interesting fact about panda bears that you heard from a tourist at the zoo, you could tell your friends to “take it with a grain of salt” since you aren’t sure whether the source of information is trustworthy.
Outside the United States, other English-speaking countries use the phrase “take it with a pinch of salt” to mean the same thing.
But why a grain or pinch of salt? Why not a twist of lime or a drizzle of olive oil?
The Roman Cure
King Mithridates VI (135–63 BCE), ruler of the Hellenistic Kingdom of Pontus, was continually in conflict with the Roman Republic for decades. His relentless attempts to build an empire made him one of Rome’s most formidable opponents and one of the most celebrated rulers of Pontus. In addition to his military endeavors, he has gone down in history as “The Poison King.”
Mithridates was obsessed with toxicology and paranoid that his enemies were planning to poison him. His fear over real and imagined assassination attempts led him to research all known toxins and their remedies, experimenting on prisoners of war to understand the effects of various substances. He attempted to make himself immune to poison, Princess Bride-style, by ingesting small doses and gradually increasing the amount to build up tolerance. Later scholars including Pliny the Elder (CE 23–79) claimed that Mithridates developed and regularly ingested a universal antidote for all known poisons, known as mithridate or mithridatium. Pliny wrote that Mithridates’ panacea contained over 50 different ingredients, including small amounts of various poisons, that were ground into power and mixed with honey. The original recipe, however, has been lost to history. Historians today believe that Mithridates likely did not actually have such an antidote, but continued to fund research while publicly bragging that he already had it to fend off potential assassination attempts.
Pliny, a Roman author and natural philosopher, amassed a great body of knowledge from studying and investigating natural and geographic phenomena. He wrote the Naturalis Historia, which claimed to cover all ancient knowledge and became an editorial model for later encyclopedias.
Plinywrote in the Naturalis Historia that after the Roman general Pompey (106–48 BCE) defeated Mithridates, he found in Mithridates’ private cabinet the following recipe for an antidote in Mithridates’ own handwriting:
Take two dried walnuts, two figs and twenty leaves of rue; pound them all together, with the addition of a grain of salt; if a person takes this mixture fasting, he will be proof against all poisons for that day.
The Latin phrase addito salis grano literally means “after having added a grain of salt,” but it was translated as “with a grain of salt” (cum grano salis in Latin) to more closely match the grammar of modern Romance languages. The idea here is that a poison or an unsavory medical cure is more easily swallowed with a small amount of salt.
The Modern Medicine
The implication that a grain of salt can mediate the effect of poison did not take on a metaphorical slant until much later, influenced by scholarly study of classical Latin texts. In 1647, the English religious commentator John Trapp wrote, “This is to be taken with a grain of salt.” No one is exactly sure what he meant, and it’s possible that this expression did not convey the same meaning it holds today. Perhaps a particular piece of commentary on the Bible was a little hard to swallow, for whatever reason.
The phrase didn’t really gain traction until the early twentieth century. It did not surface again until the August 1908 edition of The Athenæum, a U.S. literary journal. The journal included this text:
Our reasons for not accepting the author’s pictures of early Ireland without many grains of salt . . .
Apparently, the photographer’s work did not meet the editorial guidelines of the journal. By this time, it seems that the metaphor was already common enough that readers understood the meaning even when it was slightly altered for rhetorical effect.
From here, the saying “with a grain of salt”—based on the idea of using salt to make something unpalatable easier to swallow—began to catch on as a metaphor for adding a little skepticism when consuming potentially doubtful information.
The UK caught on later in the century. The earliest printed citation comes from the 1948 book Cicero & the Roman Republic:
A more critical spirit slowly developed, so that Cicero and his friends took more than the proverbial pinch of salt before swallowing everything written by these earlier authors.
This quote itself provides a good lesson on studying etymology and language change—use good judgment, vet your sources, and take things with a grain of salt when it seems that there are gaps in the historical narrative.
Corwell, F. H. Cicero & the Roman Republic. Pelican Book, 1948.
Hall-Geisel, Kristen. “What Does It Mean to ‘Take It with a Grain of Salt’?” How Stuff Works, June 30, 2020. https://people.howstuffworks.com/grain-of-salt.htm.
Hyden, Mark. “Mithridates’ Poison Elixir: Fact or Fiction?” World History Encyclopedia, June 2, 2016. https://www.worldhistory.org/article/906/mithridates-poison-elixir-fact-or-fiction/.
Gutoskey, Ellen. “Why Do We Tell People to Take Something ‘With a Grain of Salt’?” Mental Floss, September 22, 2021, https://www.mentalfloss.com/article/648536/take-it-grain-salt-meaning-and-origins.
Martin, Gary. “The Meaning and Origin of the Expression: Take with a Grain of Salt.” The Phrase Finder. Retrieved October 11, 2021, from https://www.phrases.org.uk/meanings/take-with-a-grain-of-salt.html.
The Idioms. “Take with a grain of salt.” https://www.theidioms.com/take-with-a-grain-of-salt/.
Wikipedia. “Pliny the Elder.” Retrieved October 11, 2021, from https://en.wikipedia.org/wiki/Pliny_the_Elder.