When Beijing crosstalk fan Wang Litang felt he had been misled by a celebrity endorsement for a weight-loss product, he did what most mainland consumers would not dream of doing - he took legal action. Mr Wang's lawsuit, filed last July, alleged fraudulent advertising to promote the slimming tea Zang Mi Pai You. He named crosstalk comedian Guo Degang, who promoted the product, the manufacturer and a local newspaper that carried the advertisements in the writ. As the mainland economy is booming, an increasing number of companies are eager to use local and international celebrities to promote their products. Last month the Consumers' Association in Beijing issued its third 'endorsement' alert since 2004. Prompted by complaints from people dissatisfied with goods promoted by their icons, the association asked celebrities to be cautious when signing up for brand endorsements. It also found that a female star featured in an advertisement saying that a certain cosmetic made her face look whiter had later admitted in public that she always used another brand. Mr Wang, who said he bought two boxes of Zang Mi Pai You for a total of 58 yuan because of Guo's colloquial crosstalk style, felt he had been misled by his idol. 'I saw several full-page advertisements published in a local newspaper boasting that Zang Mi Pai You [meaning it came from Tibetan tea] could trim fat stomachs in just two weeks. But it has not had that effect on me,' Mr Wang, 62, said. His hopes were shattered when Zang Mi Pai You was exposed last year as not originating from Tibetan tea. Moreover, its manufacturer was not a Hong Kong-based institute it claimed to be, and the product was not licensed. On Tuesday the Xuanwu district court in Beijing accepted another lawsuit against Guo from a woman surnamed Zhang who claimed that she had also been cheated by Guo through his promotion of the tea. The most recent case of misleading promotion involved actress Fu Yiwei singing the praises of a Hu Shi Fu brand pot, claiming it to be the world's first non-smoke and non-stick pot made with materials used to coat aircraft wings. But experts from a materials testing institute told CCTV that the pot was made from nothing more than plain aluminium. Guo and Fu are not alone on the mainland in finding their endorsed products under fire for being fakes or having grossly exaggerated qualities. In 2005, Hong Kong star Carina Lau was sued by a Jiangxi consumer who accused her of deception in an SK-II cosmetics advertisement. The woman said that instead of having fewer wrinkles, as Lau promised, she had developed skin problems after using the costly cosmetics. Fudan University advertising professor Yu Zhenwei said celebrities sometimes 'exploited the trust of the public'. According to Professor Yu, there was no accurate data on how much influence stars had on consumers' choices, but many mainlanders lacked maturity and believed almost everything in the media. The Beijing Chongwen District Court has agreed to hear the Wang-Zang Mi Pai You case but defendant Guo insists he is being unjustly blamed. On his blog, he said he had taken the slimming tea and that it had worked for him. He also said he had checked the product's licence but did not realise it was fake. But Mr Wang does not accept Guo's explanation. He said stars should be responsible to the public for their deeds. 'I think he [Guo] should have taken the initiative and investigated whether that company and its products were truthful,' Mr Wang said. Beijing-based lawyer Liu Xiaoyuan called for China's advertising law to be changed to hold individuals responsible if the products they endorse are fakes. 'The present Advertising Law was made in 1994 when few companies hired stars as image ambassadors. The law only refers to manufacturers, distributors and other organisations involved in the advertisements as being responsible,' Mr Liu said. Joseph Wang, vice-chairman of Ogilvy and Mather China, said stars should have an obligation to make sure products they endorsed, especially food and cosmetics, had qualities as claimed in advertisements.