London 2012 gold medallist Mariya Savinova has been stripped of her 800m title and banned until 2019.
The Russian has had all her results from July 2010 to August 2013 annulled after being found guilty of doping.
Savinova beat South Africa’s Caster Semenya into second at the London Olympics and the 2011 Worlds in Daegu.
The 31-year-old also beat Britain’s Jenny Meadows into to bronze at the 2010 Europeans. Both athletes could now have their medals upgraded.
Savinova will also lose her 800m gold from the 2011 World Championships and the European Championships in 2010.
And she will forfeit a World Championship silver from 2013 and will be suspended for four years, backdated to 2015.
A Court of Arbitration for Sport statement read: “On the basis of clear evidence, including the evidence derived from her biological passport (ABP), Mariya Savinova is found to have been engaged in using doping from 26 July 2010 (the eve of the European Championship in Barcelona) through to 19 August 2013 (the day after the World Championship in Moscow).
“As a consequence, a four-year period of ineligibility, beginning on 24 August 2015, has been imposed and all results achieved between 26 July 2010 and 19 August 2013, are disqualified and any prizes, medals, prize and appearance money forfeited.”
Savinova was one of five Russian athletes named in a World Anti-Doping Agency (Wada) report into doping.
She has not raced since 2013 after being suspended during an investigation sparked by the release of undercover footage filmed by whistleblower Yuliya Stepanova.
Should the International Olympic Committee decide to reallocate the medals from the London 2012 final, Semenya would be awarded a second gold after she claimed the 800m title in Rio last summer.
Savinova is now the second Russian finalist from that race to have been retrospectively banned – after Yelena Arzhakova – while a third – bronze medallist Ekaterina Poistogova – is also under investigation for doping.