Incapacitating agent is a chemical or biological agent which renders a person unable to harm themselves or others, regardless of consciousness.

Project MKUltra was an illegal human experiments program designed and undertaken by the U.S. Central Intelligence Agency (CIA) to develop procedures and identify drugs that could be used during interrogations to weaken people and force confessions through brainwashing and psychological torture. It began in 1953 and was halted in 1973. MKUltra used numerous methods to manipulate its subjects' mental states and brain functions, such as the covert administration of high doses of psychoactive drugs and other chemicals without the subjects' consent, electroshocks, hypnosis, sensory deprivation, isolation, verbal and sexual abuse, and other forms of torture.