Hoang Anh Tuan at the 2009 Southeast Asian Games
Vietnam's second-ever Olympic medallist, Hoang Anh Tuan, has been banned from weightlifting and will miss the London Olympics.
The International Weightlifting Federation have imposed a two-year ban after samples taken at the 2010 World Weightlifting Championships in Turkey tested positive for a banned substance.
Tuan, a silver medallist from the 2008 Olympics, will therefore not compete at the London 2012 Games.
He has claimed that the substance may have been present in flu medicines he took earlier in the year.
Vietnam have only ever won one other Olympic medal - another silver medal won by taekwondo fighter Tran Hieu Ngan in 2000.
Tuan's success in Beijing was widely celebrated and he was named 2008 Vietnam Sportsman of the Year.
Until now he represented Vietnam's best hope for a medal at the London Games.
Tuan has had a difficult two years since Beijing. After failing to win a medal at the 2009 Southeast Asian Games in Laos, Tuan was seen publicly weeping on live television.
The hostile reaction from the Vietnamese media was enough for Tuan to consider leaving the sport.
"The public pressure is unbearable at times, that's why I thought about quitting," he told the BBC last year.
Tuan was set to make a comeback in October, 2010 at the World Championships but he could only manage fourth place. And after his 'A' sample from the tournament failed a drugs test, Tuan was withdrawn from the Asian Games in Guangzhou, China.
He will now be excluded from any involvement in competition until 18 September 2012.