truth serum

American  

[trooth seer-uhm] / ˈtruθ ˌsɪər əm /

Often truth drug

noun

1. a drug, as the barbiturate thiopental, that induces in the subject a desire to talk or a state of heightened suggestibility, used in psychotherapy and in interrogation to discover repressed or consciously withheld information.

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Etymology

Origin of truth serum

First recorded in 1920–25

Example Sentences

As the YouTube hit demonstrates, hot sauce isn’t just for daredevils and masochists: It’s a truth serum.

From The Wall Street Journal • Nov. 20, 2025

Though occasionally used in court, forensic hypnosis was no truth serum.

From Los Angeles Times • Apr. 24, 2023

And if Carroll was given a dose of truth serum, the hunch here is he would acknowledge this as his most satisfying season in Seattle.

From Seattle Times • Jan. 9, 2023

But you know, if you really have me under truth serum and say, you know, how confident am I?

From New York Times • Dec. 10, 2021

“Most GPs can’t resist the truth serum, either,” I say.

From "Allegiant" by Veronica Roth