Malcolm McDowell's eyes were anesthetized for the torture scenes so that he would film for periods of time without too much discomfort. Nevertheless his corneas got repeatedly scratched by the metal lid locks.

Many of the continuity errors are not in fact errors. Stanley Kubrick purposely included many continuity errors as a way of creating a feeling of disorientation for the audience. That is why people's positions change, props are reorganized, and hats (and other articles of clothing) appear and disappear.

There are no opening credits after the title, which is followed by the opening shot of Alex the Droog. Although it is now commonplace for major films to not have opening credits, in 1971 it was considered rather unusual and was considered a trademark of director Stanley Kubrick.

In 1973, a new version of "A Clockwork Orange" was released to theaters with an MPAA rating of "R", replacing the previous "X". The new version contained approximately 31 seconds of replacement, less lascivious footage for two scenes: the high speed (2 fps) orgy in Alex's bedroom, and the Ludovico rape scene. The bedroom scene was made more comical by having one of the girls fall off the bed and Alex joins her down there. The Ludovico rape scene was altered in that the scenes with the first two droogs was from the side and waist-up, so it is less explicit. The third droog was removed completely and replaced with a close-up of one of the doctor's face as they are watching Alex's treatment.

Edited from Triumph of the Will (1935)