Criminal suspects, while under the influence of barbiturate drugs, may deliberately withhold information, persist in giving untruthful answers, or falsely confess to crimes they have not committed. Narcoanalysis is of doubtful value when used for the purpose of obtaining confessions to crimes. For ethical reasons the psychiatrist is advised against performing narcoanalysis when the examination is requested as an aid to criminal investigation. Narcoanalysis is sometimes of value in the psychiatric examination of criminal suspects who have entered a plea of insanity. Information so obtained should not be used as evidence in determining the innocence or guilt of the accused person, unless it is with his consent and his attorney's approval. Indications and contraindications for narcoanalysis are described, as well as some criteria for evaluating the reliability of the individual examination.