The 62-year-old actor, who became a household name playing Phoebe Buffay on the beloved sitcom, was close to the rest of the cast of the show but behind the scenes, things could be "intense", she said.
Insults were hurled if an actor messed up their line and there was a culture of lewd discussions, according to Kudrow.
"There was definitely mean stuff going on behind the scenes," she told The Times magazine, describing a largely male writers' room of 12-15 people.
"Don't forget we were recording in front of a live audience of 400, and if you messed up one of these writers' lines or it didn't get the perfect response they could be like, 'Can't the bitch f***ing read? She's not even trying. She f***ed up my line.'"Â
And Kudrow also referred to Friends assistant Amaani Lyle's failed legal action for sexual harassment, in which she alleged the writers - whose brainstorming she was tasked with transcribing - had discussed sleeping with Jennifer Aniston and Courteney Cox, feigning masturbation and receiving oral sex.
"And we know that back in the room the guys would be up late discussing their sexual fantasies about Jennifer and Courteney. It was intense.
"Oh, it could be brutal, but these guys - and it was mostly men in there - were sitting up until 3am trying to write the show so my attitude was, 'Say what you like about me behind my back because then it doesn't matter.' "
Kudrow married advertising executive Michel Stern in 1995, months before Friends started, and she thinks her stable home life helped her to avoid as much scrutiny as her co-stars.
"For sure, and all because I married early and outside the business," she said.
"No one was interested. There was no story."
Kudrow, who has 27-year-old son Julian with Stern, stressed her life at home was different to being on set.
"And very early on I was pretty clear: actors on a big show are well paid and really looked after. But you cannot take that attitude home with you. At home it's family, life, kids."
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