It's a common superstition among actors, directors, and stagehands to avoid saying aloud the name Macbeth while in the theatre itself, under the belief that to do so will bring bad luck and/or curse the production. To avoid it, most theatre people refer to the Shakespearean tragedy as "The Scottish Play."

According to folklore, Macbeth was cursed from the beginning. It was widely believed that a coven of witches objected to Shakespeare using real incantations in the script, so they put a curse on the play.

Legend has it the play’s first performance (around 1606) was riddled with disaster. The actor playing Lady Macbeth died suddenly, so Shakespeare himself had to take on the part. Other rumored mishaps include real daggers being used in place of stage props for the murder of King Duncan (resulting in the actor’s death).

The Astor Place Riot in New York in 1849, caused by rivalry between American actor Edwin Forrest and English actor William Charles Macready, resulted in at least 20 deaths and over 100 injuries. Both Forrest and Macready were playing Macbeth in opposing productions at the time.

Other productions have been plagued with accidents, including actors falling off the stage, mysterious deaths, and even narrow misses by falling stage weights, as happened to Laurence Olivier at the Old Vic in 1937.

Macbeth was also seen as unlucky by theatre companies as it usually meant that the theatre was in financial trouble. Macbeth was (and still is) a popular play that was guaranteed an income so if it was suddenly announced it could mean that the theatre was struggling. 

So how can you avoid catastrophe if you accidentally utter the play that shall not be named? Exit the theatre, spin around three times, spit, curse and then knock on the theatre door to be allowed back in.