Russia was stripped of their women's 4 x 400m relay silver medal from the London 2012 Olympics after Antonina Krivoshapka tested positive for drugs in the re-testing of her sample, the International Olympic Committee said on Wednesday.
Krivoshapka, who was part of the silver medal-winning women's relay team, was disqualified after a positive test for the anabolic steroid turinabol, the IOC said. Her relay teammates will also be stripped of their medals.
The IOC is re-testing hundreds of samples from the London and Beijing Olympics in an effort to detect any cheats using newer methods or looking for drugs that were at the time undetectable.
More than 100 athletes have so far tested positive in these re-tests, with Russia having the most cases per nation.
Russia's Olympic team was partially banned from last year's Rio de Janeiro Olympics over a state-backed doping scandal.
Turkish boxer Adem Kilicci and Russian discus thrower Vera Ganeeva were also disqualified from London for testing positive for the same substance.