Mark Dightam, who was eleven when he controversially appeared full frontally naked as MacDuff's son, was not allowed to see the film when it was released because it had been classified AA and he was under 14 at the time.
When crew members suggested to Roman Polanski that perhaps the film was too unrealistically gory for its own good, Polanski reportedly replied, "I know violence. You should've seen my house last summer."
Filming began with four grueling weeks in Snowdonia National Park. A cameraman was nearly killed on the first day when a fierce wind blew him into a crevice.
In her memoirs, Marianne Faithfull recalls screen testing for the role of Lady Macbeth at the request of Roman Polanski. However, when her heroin use became obvious to Polanski during the test, she lost the role.
The scene in which Macbeth's thugs massacre Macduff's household was based on Roman Polanski's memory of SS officers ransacking his house as a child.