A steamy spy thriller that has caused a sensation in China has attracted the ire of the health police, with doctors warning film enthusiasts against imitating the ambitious sexual endeavours depicted in the film.

Lust, Caution, the latest film from Ang Lee, the Oscar-winning director, has become a box-office hit in China. But it is also attracting tens of millions of viewers who are downloading pirated versions of the film, containing at least seven minutes of bedtime action cut by China’s censors.

As a result of the mass interest, medical officials have taken it upon themselves to advise those with access to the uncensored version: do not try this at home. A reporter for the Information Times surveyed 20 people who had seen the uncensored film, which is set in Shanghai during the Second World War. He also spoke to medical experts about the several minutes of sexual gymnastics – often violent and almost always erotic – that help to explain the attraction between a naive young student and a traitorous and vicious Chinese police chief.

He wrote: “Highly difficult sexual positions can cause unnecessary harm to both the male and female body and, hence, people should not be imitating what they see on the big screen.”

The Information Times quoted Yu Zaoze, a gynaecologist with the Guangzhou Modern Hospital. “Most of the sexual manoeuvres in Lust, Caution are abnormal body positions,” he said. “Only women with comparatively flexible bodies that have gymastics or yoga experience are able to perform them. For average people to blindly copy them could lead to unnecessary physical harm.”

The damage to viewers may not only be physical. A Chinese company focusing on software to combat computer viruses has given warning that pirate downloads of the film could be embedded with viruses and 15 per cent of links were contaminated. An engineer with the company was among the first to encounter the virus last week – his screen went blank and he lost his messaging password.

The film, which is tipped to become the year’s biggest box-office success, has been a huge hit in China, reaping 90 million yuan (£6 million) in its first two weeks.

Its success is due partly to Ang Lee’s Taiwanese origins – most Chinese regard the director as one of their own – as well as its theme of Chinese resistance to Japanese occupying forces in the Second World War.

Lee, who won the best director Oscar in 2005 for his controversial gay cowboy drama Brokeback Mountain, personally cut on-screen sex and other scenes to allow the film to pass Chinese censors. The cuts, however, prompted a flood of Chinese in southern China to cross the border into Hong Kong to see the full version.

Some have adopted a bolder approach in their quest to see the film in full. Dong Yanbin, a graduate law student, tried to sue a cinema chain and the State Administration of Radio, Film and Television for infringing his rights by screening the film with an incomplete plot structure. (By Jane Macartney)