Truth serum was a drug used to induce an inclination to talk without inhibition and to reveal withheld information. The IT-O Interrogation Units of the Galactic Empire could administer doses of truth serum to a prisoner in order to extract information from him or her. When Kanan Jarrus endured the Grand Inquisitor's torture aboard the Sovereign, he was administered truth serum.
- Catalyst: A Rogue One Novel (Mentioned only)
- Star Wars Rebels – "Rebel Resolve" (First appearance)
- Battle to the End (First identified as Truth serum)
- A New Hope: The Princess, the Scoundrel, and the Farm Boy