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The Debunker: Is There a Clinical Fear of Getting Peanut Butter Stuck on the Roof of Your Mouth?

by Ken Jennings

Do you celebrate National Peanut Day every September 13? Of course, we all do! It's a cruel coincidence that the peanut's big moment comes every fall, just as kids are returning to their increasingly peanut-free schools. If you're not allergic, you probably love peanuts in your trail mix, on sundaes, or in sandwiches (butter form only). But how much do you really know about the protein-rich foodstuff? Jeopardy!'s Ken Jennings is here to tell us that a lot of your favorite facts about this beloved snack are just plain nuts.

The Debunker: Is There a Clinical Fear of Getting Peanut Butter Stuck on the Roof of Your Mouth?

There's an eighteen-letter-word that's been a trivia favorite for decades, appearing everywhere from board games to Snapple caps to reference books: arachibutyrophobia. This scary-sounding psychiatric disorder is usually cited as something fairly harmless-seeming: "the fear of getting peanut butter stuck on the roof of your mouth." Boy, psychiatrists have a phobia for everything these days, don't they?!?

good grief

The etymology of the word seems sensible enough: "arachi-" comes from Arachis, the genus to which the peanut plant belongs. (Webster's speculates that this may be because of this family of plants' arachnid-like tendrils that extend down and grow under the soil.) Butyrum is the Latin word for butter. There's no "roof of your mouth" in there, but "arachibutyrophobia" does sound plausibly like what a scientist would call the irrational fear of peanut butter.

The problem is that I can find no mention of arachibutyrophobia in any medical literature, except as a recent oddity sourced from the Internet. The source of this iffy word is usually given as the 1985 Modesty Blaise novel Dead Man's Handle, by Peter O'Donnell, or a May 19, 1982 Peanuts strip by Charles Schulz, in which Sally reads a school report on the word. Both those attributions are wrong, however. The word was actually introduced to America by the 1975 pop reference classic The People's Almanac, in which it's included in a list of phobias. Prior to 1975, I can find no citations of arachibutyrophobia anywhere; afterward, newspaper columnists couldn't get enough of it. So I reached out to David Wallechinsky, who wrote the People's Almanac books along with his father, novelist Irving Wallace. Could "arachibutyrophobia" have been their little joke? He reports that the book's phobia list was written by lexicographer Robert Hendrickson, who did submit a bibliography which included interviews, but that those files were recently donated to Claremont University. Unless any readers in the Los Angeles area want to stop by the Claremont library and delve further, the arachibutyrophobia trail is cold. As cold as a thick, suffocating layer of peanut butter coating the roof of your mouth.

Quick Quiz: What word for "pleasant" or "tasty" comes to us from the Latin word for the roof of the mouth?

Ken Jennings is the author of eleven books, most recently his Junior Genius Guides, Because I Said So!, and Maphead. He's also the proud owner of an underwhelming Bag o' Crap. Follow him at or on Twitter as @KenJennings.