Uzbek judo silver medallist Shokir Muminov has been disqualified after testing positive for the banned stimulant methylhexaneamine, an Olympic Council of Asia official said on Friday.
OCA medical committee chairman Dr Mani Jegathesan told reporters the presence of the drug in the athlete's urine sample had been deemed "sufficient for us to take action".
"The athlete has been disqualified from the competition as well as these Games and his performance in the competition has been nullified, his medal withdrawn and appropriate adjustment made to the results," Jegathesan said.
Muminov, 27, a bronze medallist at the 2006 Doha Games, was beaten in the men's 81 kgs gold medal bout by South Korea's Kim Jae-bum on Sunday.
Methylhexaneamine, commonly used in nasal decongestants, was added to the World Anti-Doping Agency's (WADA) banned list this year. It can also be found in bodybuilding and dietary supplements.
A raft of athletes across an array of sports have tested positive for the stimulant in recent weeks.
South Africa rugby international Chiliboy Ralapelle and winger Bjorn Basson returned positive tests after the Springboks' victory over Ireland on November 6.
Osayemi Oludamola was one of two Nigerian athletes banned at the Commonwealth Games last month where she had her 100 metres sprint gold medal stripped. An Indian race walker was also provisionally suspended at Delhi for the stimulant.
A spokesperson for the Uzbek delegation declined to comment.
Authorities had carried out 750 urine and 50 blood tests at the Asian Games since Nov. 6, Jegathesan said, half the number they intended to carry out for the November 12-27 multi-sport event.
Muminov's results would be forwarded to Uzbek authorities, the International Judo Federation and the World Anti-Doping Agency for "further action on their part," Jegathesan said.
Doping shame also engulfed Uzbekistan's delegation at the Doha 2006 Asian Games, where two of their athletes were among four weightlifters disqualified for failing drug tests.
Some 9,700 athletes from 45 countries are competing in 42 sports at the Guangzhou Asian Games in southern China, which run until November. 27.