Bowdlerise/Theater

The very first words (sung by the black chorus) of the musical Show Boat have been Bowdlerized in various ways over the years. The most faithful of the three film versions (1936, Universal) began "darkies all work on de Mississippi." The major Broadway revival in 1946 (for which Oscar Hammerstein made a few other revisions) changed the line to "colored folks work on de Mississippi," which has become the most commonly seen variant. At least this keeps the sense of the following line ("...while de white folks play") intact, unlike another once common variant: "here we all work on de Mississippi." The 1966 Lincoln Center production, like MGM's 1951 film, dodged the subject by abridging the opening chorus (and the second verse to "Ol' Man River," which reprises the excised section); in these versions, to quote theatre historian Miles Kreuger, nobody worked on the Mississippi. Kreuger and a few other musical theatre buffs, citing the fairly serious treatment of race relations in Show Boat, have expressed their preference for the original opening lines as they were sung in 1927:

"Niggers all work on de Mississippi,
Niggers all work while de white folks play..."

In The Fifties, Ira Gershwin replaced all uses of "nigger" in Porgy and Bess: about twenty, by his count. It's fortunate that the earlier stage version of Porgy has succumbed to Adaptation Displacement, as it used the word considerably more often.
Passages of three Gilbert and Sullivan patter songs from The Mikado and Princess Ida were rewritten in the forties to get rid of that same word. As Psyche says to the girl students in Princess Ida, "you will get them Bowdlerised" in this manner:

"And the niggers they'll be bleaching" => "And they'll practise what they're preaching" (Princess Ida, "They Intend to Send a Wire to the Moon")
"There's the nigger serenader, and the others of his race" => "There's the banjo serenader, and the others of his race" (The Mikado, "I've Got a Little List")
"Is blacked like a nigger with permanent walnut juice" => "Is painted with vigour and permanent walnut juice" (The Mikado, "My Object All Sublime")

- The forties? Gilbert himself rewrote parts of The Mikado to that end at least, after American audiences pointed out that, while the word may have been innocent in Victorian Britain, across the pond it was rather closer to the modern implications.
- Also in Princess Ida, the Lady Psyche suggests that her students should get the works of Juvenal bowdlerised. Given the content of Juvenal's writing and the Dworkin-esque nature of the school's morality I can't imagine there'd be much left to read...
There was some Bowdlerization on original cast albums of the 1960s and earlier, though it ought to be noted that even the original lyrics used Gosh Dang It to Heck to an inconsistent extent.
- One of the most consistently censored expressions was "son of a bitch," three instances of which were removed from The Most Happy Fella.
- In "Get Me to the Church On Time" from My Fair Lady, "For God's sake, get me to the church on time" became "Be sure and get me to the church on time."
In the original Broadway version of Sweeney Todd: The Demon Barber of Fleet Street, there was the song "Johanna" sung by Judge Turpin, where he said how suddenly grown up Johanna seemed, and how beautiful she was, while he's watching her through a hole on the wall of her room that Turpin did himself. He starts flagellating himself as the song goes on, and climaxes (the stage direction says so) while screaming "God!!!" The Vocal Score says it was cut for reasons of time, but it was squicky enough to just let it out. True, Turpin's crush on Johanna is showed in the play and is a plot point, but that song was more disturbing than just him saying that he wanted to marry her.
When musical Spring Awakening performed a medley at the Tony Awards, several lyrics to "The Bitch of Living" were changed to please CBS. Including, among others, "nothing but your hand" to "getting what you can" and "breasts" to "chest". The company then lampshades the censorship in the "Totally Fucked" portion by censoring themselves on the words "ass" and "fucked".
- However, when the show performed another medley on Good Morning America, part of "Totally Fucked" was also performed, but this time with the phrase "totally fucked" changed to "totally stuck" and "kiss your sorry ass goodbye" as "kiss your sorry life goodbye".
The original published version of the song "You Can Drive A Person Crazy" from Company altered the last word of "if a person was a fag" to "drag"; some singers use this. For the 1996 revival of the show, Stephen Sondheim rewrote the line and its complementary rhyme:

I could understand a person
If he said to go away
I could understand a person
If he happened to be gay

- It has since been restored to the original version.
A modern example of Bowdlerisation is when The Taming of the Shrew is changed to make it more "feminist" especially the ending. The most ridiculous examples have Petruchio and Katharine end up with a happy marriage where all their verbal abuse has ended, even though this was what neither character wanted from the other in the first place.
- It's not the first time The Taming of the Shrew has been bowdlerized. Many high school versions of the play remove Petruchio's line "What? With my tongue in your tail?"
Some sexual allusions in The Rise and Fall of the City of Mahagonny were censored in the original German production: the "love" scene no longer depicted a busy brothel, and a duet for Jim and Jenny was interpolated to compensate for the scene's abridgment. The lyrics of the recurring chorus which helps introduce that scene were changed to avoid use of the word "Liebesakt".
Some school productions of Les Miserables leave in "send the slut away" and "I should have known the bitch could bite" but change "Damn their warnings, damn their lies" to "Blast their warnings, blast their lies." The "Lovely Ladies" song is also surprisingly uncensored, while Valjean hitting Javert over the head with a chair is removed.
- The chair thing might have more to do with the potential physical danger involved than with censoring.
In all twentieth-century versions of Starlight Express, Ashley carried a pack of cigarettes and frequently mimed smoking them. The second U.S. tour made her a smoking car In Name Only and heavily implied that she'd turned to promiscuous sex instead, which would be fine if it hadn't been presented in the sleaziest manner possible.
- The Broadway adaptation of the show rewrote "Belle the Sleeping Car" to emphasize Belle's career as a prostitute, which would ordinarily be the opposite of this trope...except that the Broadway version removed some drug references and greatly increased the comedic factor of the character, rather than portraying her as the resigned, despondent old woman she was in the London show. See this link to contrast the two.
- The 1992 London revamp excised the Serial Killer villain, who provided the catalyst for most of the conflict in act two. Ironically, the rewritten reversal was more violent than before.
At least one High School production of A Chorus Line turned the song "Tits and Ass" into "This and That". Which, in a way, turned a song about stage titillation into a song about prostitution (!).
Many productions of Guys and Dolls have the Hot Box dancers dressed in less Stripperific costumes.
The school edition of Avenue Q completely rewrites "The Internet Is for Porn" as "My Social Life is Online," a song about Facebook and other networking sites.
This trope actually makes sense for the school edition of Once On This Island, because the cast consists wholly of But Not Too Black wealthy folk and very dark-skinned peasants. Their racial divide is a major source of their conflict, but this typecasting isn't very common in the average school, so this divide is removed, leaving only the emphasis between the poor and the rich.