Introduction Narco analysis test once again is in the limelight in the contest of Aarushi Murder case. Earlier it was used in the Nithari village (Noida) serial killings, Telgi Stamp paper scam, Arun Bhat kidnapping case in Gujarat, Godhra carnage probe and others. The search for effective tools for interrogation is probably as old as man’s need to obtain information from an unco-operative source. Development of new tools of investigation has led to the emergence of scientific tools of interrogation and criminal investigation like Narco analysis test. However, its application must be assessed objectively so that it can be replaced by existing conventional methods of interrogation, which brought shame, ignominy and disrepute to police leading to the erosion of credibility of criminal justice system. Narco analysis test can be effective as an alternative to barbaric third degree methods. Care however must be taken to ensure that this procedure ....