Theatregoers were "disgusted" by language used by characters in a new musical, Betty Blue Eyes, produced by Sir Cameron Mackintosh.
Barbara Cramer went to see the musical at the Novello Theatre in London last week with 18 members of her social group.
She said they were shocked to hear the words "Yid" and "Jew boy" used by characters.
"A character was talking about inviting people down from Manchester for a celebration of the Royal Wedding and referred to them as Yids. And 'Jew boy' was used during the second half, said Mrs Cramer, of Bricket Wood, St Albans.
"I know the show is about a pig, but we are not the only race where eating pig is forbidden. Everyone I was sitting with was incensed by it, and we have written to the producers.
"It ruined my evening. No other minority was attacked this way as far as I can recall."
Both the scriptwriters, Dan Lipman and Ron Cowan, are Jewish. The musical, set in 1947, is adapted from Alan Bennett and Malcolm Mowbray's A Private Function.
Managing director Nick Allott, of Cameron Mackintosh Limited, said the comments were intended to show the nasty side of a character.
He said: "Yes, the two phrases are used, but they're used by the most unpleasant character, Dr James Swaby. He's rude about everyone, he's a snob, and he's everything that was unpleasant in post-war Britain.
"He's a frustrated, vile man. Although it's a musical comedy, it's actually a very accurate portrayal of austerity Britain."
Mr Lipman said: "Ron and I are both Jewish and of course we are sensitive to this. But I think all of us feel strongly that the words give the show a reality that's very important.
"This isn't like going to see a stand-up comedian who just spews obscene language. But I'm really sorry the evening was ruined for Ms Cramer."