London 2012 Olympic 1500m champion Asli Cakir Alptekin has been stripped of her gold medal for doping.
The Turkish athlete has also been banned for eight years, the Court of Arbitration for Sport confirmed.
An appeal by world governing body the IAAF was upheld after the 29-year-old was cleared in Turkey.
Straight after the race, Britain’s Lisa Dobriskey, who finished ninth, told BBC Radio 5 live: “I don’t believe I’m competing on a level playing field.”
Alptekin served a two-year ban after a positive test as a junior in 2004.
Her competitive results obtained since July 2010 have been disqualified after abnormal values were found in blood samples.
The case comes amid a series of allegations of doping in athletics made by the Sunday Times and a German broadcaster.
Last week the IAAF said it was suspending 28 athletes as a result of suspicious findings in doping tests.
