A popular Chinese medical information site has been censored by authorities for "violation of relevant laws and regulations", months after its criticism of a government-backed herbal Covid-19 treatment sent shares in a pharmaceutical giant tumbling.

DXY, which counts tech giant Tencent among its investors and runs a host of health-related services, previously questioned the value of Lianhua Qingwen, a herbal remedy marketed for fever and sore throats, as a Covid-19 treatment.

China approved the concoction -- made up of ingredients like honeysuckle and apricot seeds -- as a Covid-19 treatment in 2020, and it was distributed to Shanghai residents during the city's outbreak this year.

DXY's article was part of a wave of reports that caused shares in Lianhua Qingwen's producer -- one of China's largest traditional medicine companies -- to plunge.

The website has now been banned from posting on at least five of its Weibo social media accounts, with a notice at the top of its official page saying that due to "violation of relevant laws and regulations, this user is currently prohibited from posting".

DXY's official WeChat accounts, which typically publish multiple articles a day on medical topics, have not been updated since Monday.

The Weibo notice did not specify which regulations had been violated by DXY, which did not immediately respond to AFP's request for comment.

The Chinese government has increasingly promoted traditional medicine at home and abroad in recent years, often with nationalistic undertones.

DXY's coverage prompted criticism that it was targeting traditional Chinese medicine (TCM) in order to promote Western pharmaceuticals.

The United States and other countries have warned there is no evidence Lianhua Qingwen works to prevent or cure Covid-19, even as it has increasingly been promoted by government authorities in China and Hong Kong.

The US Food and Drug Administration has said it has not approved Lianhua Qingwen and that coronavirus-related claims about it were "not supported by competent and reliable scientific evidence".

Beijing issued its first white paper on TCM in 2016, laying out plans to build medicine centres and dispatch practitioners to developing countries in Africa and Southeast Asia.

President Xi Jinping has described TCM as a "treasure of Chinese civilisation" and has said that it should be given as much weight as other treatments.

Beijing's National Health Commission has also dispatched TCM practitioners as part of its medical reinforcement teams sent to fight Covid-19 outbreaks across the country.