truth serum

[ trooth seer-uh m ]
/ ˈtruθ ˌsɪər əm /


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.
Often truth drug [trooth druhg] /ˈtruθ ˌdrʌg/.
Compare narcoanalysis.

Origin of truth serum

First recorded in 1920–25 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for truth drug

truth drug

truth serum


informal any of various drugs supposed to have the property of making people tell the truth, as by relaxing them
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for truth drug

truth serum
[ trōōth ]


Any of various hypnotic or anesthetic drugs, such as scopolamine or thiopental sodium, used to induce a subject under questioning to talk without inhibition.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.