Among other things, the character Augustus Gloop in "Kalle and the chocolate factory" will be called "huge" instead of "thick".
Mrs Twits from "The twits" will be referred to as "nasty" instead of "ugly".
Even words that touch on topics such as mental health and gender are adjusted.
Among other things, the changes have angered the internationally acclaimed author Salman Rushdie, who calls the decision censorship.
"Roald Dahl was no angel but this is absurd censorship.
Puffin books and Dahl's estate should be ashamed," writes the author on social media.
The freedom of expression organization Amerikanska Pen is also critical and believes that the changes are worrying.
"If we embark on this path of trying to correct perceived inaccuracies instead of letting the reader receive and react to the books as they are written, we risk distorting the works of great authors as well as obscuring the important lens through which literature turns towards society," writes the organisation's CEO Suzanne Nossel on Twitter.
"Not unusual"
Roald Dahl passed away in 1990 aged 74 and his collected works have sold over 300 million copies.
But he was also controversial and made several anti-Semitic statements during his lifetime, something his family apologized for.
The publisher Puffin is behind the changes in the British editions together with the organization The Roald Dahl story company.
They believe that the purpose of the changes is to make the author's children's books more modern and inclusive, also that the changes are "small and carefully considered".
"When publishing a new edition of a book that was written a long time ago, it is not uncommon to review the language and update other details, such as the book's cover and page layout," says a spokesperson for The Roald Dahl story company in a statement.