Asian Games chiefs on Friday expelled China's gold medal-winning women's hammer thrower Zhang Wenxiu in the biggest doping case of the giant event.
The Olympic Council of Asia said 28-year-old Zhang, who won a bronze medal at the 2007 world championships and 2008 Olympics, had tested positive for the anabolic agent zeranol.
"The competitor has been disqualified from the competition as well as these Games," said an OCA statement, which added that the gold medal had been withdrawn.
Zhang is the sixth athlete to be kicked out of the Games in Incheon, South Korea for doping and the second gold medal-winner after Malaysia's wushu champion Tai Cheau Xuen.
Zhang hurled an Asian Games record 77.33 metres to win her third straight Asiad gold on Sunday.
Despite her disqualification, China will keep the gold as team-mate Wang Zheng came second ahead of India's Bala Manju and Masumi Aya of Japan.
Zenarol, which is banned by the World Anti-Doping Agency (WADA), is widely used to fatten livestock. Athletes are known to take it illegally for its muscle-building properties.
The Chinese Olympic Committee (COC) said it accepted the expulsion of Zhang, but stressed that deliberate doping had not been proved.
"The athlete may dope deliberately, but there also remains the possibility that the positive reading was due to her consumption of contaminated meat," the Chinese Olympic Committee (COC) said in a statement quoted by the state Xinhua news agency.
"Whatever the cause is, we respect the OCA's decision regarding Zhang's case, because the World Anti-Doping Code stipulates that athletes must bear the subsequences for the substance found in his or her body," it added.
China says it has launched a major campaign against doping in sport since a number of high=profile cases in the 1990s involving swimmers and athletes.
Eleven Chinese competitors were caught doping at the 1994 Hiroshima Asian Games.
Before the 1998 world swimming championships in Australia, customs caught a Chinese swimmer attempting to bring in a suitcase full of human growth hormone. Four Chinese swimmers were disqualified at the event for failing drug tests.
- China's 'zero tolerance' -
Over the past 15 years more than 10 Chinese athletes, including some Olympic athletes, weightlifters and swimmers, have failed tests.
But the COC said that more than 10,000 drug tests a year have been carried out on Chinese athletes over the past decade with a failure rate of just 0.02 percent. It says this is one of the lowest rates in the world.
China this month pledged one million dollars to an international fund being set up by WADA to improve research into doping.
WADA president Craig Reedie and IOC president Thomas Bach thanked Beijing for the gesture.
Reedie said China had made "strong demonstrations of support in the protection of the rights of clean athletes. China has led the way and set an example for other national governments to follow."
China's Vice Premier Liu Yandong said at the time that the government "is continuously committed to the fight against doping in sport, and the promotion of clean sport and upholding a 'zero tolerance' of doping."
Zhang follows Tai, a Tajik footballer, a Cambodian soft tennis player, an Iraqi weightlifter and a Syrian karate fighter in failing tests at the Asian Games.
The OCA says that a record 1,900 athletes out of some 9,500 in Incheon will undergo drug tests.