"Animal experts and veterinarians should also be allowed to enter the bear farms, if he wants to prove what he says," said Sun Quanhui, an official from the World Society for the Protection of Animals.

"I don't believe it at all that extracting bile is as easy and comfortable as Fang said. Why doesn't he extract the bile from his body in the same way to prove it?" wrote a female netizen from Chengdu, posting under the name Liangxiaotangtang on Sina Weibo, a popular micro-blogging site.

Bear bile is used in traditional medicine in China and other Asian countries because it is thought to have health benefits, such as detoxification, cleansing the liver and improving vision.

Years of research has shown that China can produce drug substitutes that have the same function as bear bile, said Jiang Qi, former vice-president of Shenyang Pharmaceutical University, in January.

But so far, government authorities have not approved the substitute drugs for sale on the market.