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 are generally changed from the original text to get rid of the word "nigger". This was first done in the lifetime and with the assent of W. S. Gilbert, after American audiences had pointed out that the word was a rude insult in the United States.
"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")
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," several instances of which were removed from The Most Happy Fella (though two instances of it were already supposed to be inaudibly whispered under Cleo's breath).
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 (which since then has been restored to the original version):
I could understand a person If he said to go away I could understand a person If he happened to be gay
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" (a common German term for sexual intercourse).
Some school productions of Les MisÚrables 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 (!).
Another high school changed the song to "Swerves and Curves," and song is about Val going to the health club to improve her figure instead of getting plastic surgery.
The 2013 London revival has her lyric in "And" 'tied up and raped at seven' changed to 'tied up at home at seven'.
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. Also, the show shortens the scenes with the Bad Idea Bears to focus less on drinking, changes the names of two of the characters (Lucy the Slut is now called Lucy, and Mrs. Thistletwat is now Mrs. Butz), and two songs have been removed.
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.
Some productions of The Fantasticks eliminate references to rape and replace "It Depends On What You Pay" with "Abductions (And So Forth)".
In Follies, "heck" is sometimes substituted for "hell" in "Broadway Baby," probably because the consonant sound actually fits the song's meter better. The four-letter word at the end of "The Right Girl" seems to change depending on the production, though sometimes the low-key coda is omitted so the Angry Dance can have a big finish.
The early Broadway run of Grease had much more profanity, including one of Sandy's final lines being "Nah, fuck it". After complaints were made about the language and after the film version rose in popularity, the Broadway script was gradually cleaned up to be more family-friendly. This also necessitated lyric changes to "Mooning" and "Greased' Lightnin'" (although the film had kept the original, raunchier lyrics of the latter).
The version that ran at Kingston Mines was filled with even vulgar language and ethnic slurs (ie: "Wop", "Polack") that were ordered to be cleaned up for the Broadway script. These were restored for a 40th anniversary revival in 2011.
A kid-friendly "Grease Jr."/"Grease: The School Version" script exists for schools to perform, with the run-time shortened to about 60 minutes and the plot drastically cut up for content and timing purposes. Among the noticeable edits is the removal of Rizzo's pregnancy-scare towards the end of the play.
One edition of the 1917 Sigmund Romberg operetta Maytime changes the Dance Sensation song "Jump Jim Crow" to "Dance the Do-Si-Do."
The movie rendition of Oklahoma! came out during the time of the Hayes Code, and so had to change some of the song lyrics. In the stage version of "Kansas City", the second verse contains the lines: "I could swear that she was padded from her shoulder to her heel, but later in the second act when she begun to peel, she proved that ev'rything she had was absolutely real!". The film had to change it to "I could swear that she was padded from her shoulder to her heel, and then she started dancin' and her dancin' made me feel / that every single thing she had was absolutely real!".
The theatrical play Picnic got made into a movie during the Hayes Code years, and a line about a bunch of girls getting it on with the hero was changed into a line about the hero drinking martinis with the girls. Both versions followed this line with the hero saying, "They must have thought I was Superman."
For a long time, the only version of the 1776 film (apart from the supercut on the laserdisc) was heavily edited. They cut the exchange between Franklin and Dickinson about calling an ox a bull ("he's thankful for the honor but he'd much rather have restored what's rightfully his"/"when did you first notice they were missing, sir") and Washington's complaint about the whoring and drinking in New Brunswick. And because it offended Nixon, the song "Cool, Cool, Considerate Men." These were later restored with the DVD release.