China has banned newspapers, publishers and website-owners from using foreign words - particularly English ones.
China's state press and publishing body said such words were sullying the purity of the Chinese language.
It said standardised Chinese should be the norm: the press should avoid foreign abbreviations and acronyms, as well as "Chinglish" - which is a mix of English and Chinese.
The order also extends existing warnings that applied to radio and TV.
China's General Administration of Press and Publication said that with economic and social development, foreign languages were increasingly being used in all types of publications in China.
It said such use had "seriously damaged" the purity of the Chinese language and resulted in "adverse social impacts" on the cultural environment, reported the People's Daily newspaper.
If words must be written in a foreign language, an explanation in Chinese is required, the state body said.