Cross country skier Olga Danilova tested positive for darbepoetin, which boosts production of oxygen-carrying red blood cells, after winning her medals at the 2002 Olympics in Salt Lake City. Danilova was not immediately stripped of her medals in the women's pursuit and her silver from the 10-kilometer classic, but lost them after a Court of Arbitration for Sport ruling in December 2003. REUTERS

Larisa Lazutina tested positive for darbepoetin as the 2002 Salt Lake City Games drew to a close. Lazutina was stripped of the gold medal she captured during the cross-country 30-kilometer classic event as well as two silvers for cross-country skiing, women's 15 km freestyle and cross-country skiing, women's 5 km + 5 km combined pursuit.
REUTERS/William Webster

Irina Korzhanenko was stripped of her gold for women's shot put after failing a drug test for the anabolic steroid stanozolol, an anabolic steroid favored by athletes and bodybuilders attempting to lose fat while retaining lean body mass, at the 2004 Athens Olympics. REUTERS/Kieran Doherty

Russia was ordered in August 2016 to return its gold medals from the 2008 Beijing Olympics 4x100m women's relay after Yulia Chermoshanskaya tested positive for a banned substance in a re-analysis of her sample. The IOC disqualified her for testing positive for steroid use. Chermoshanskaya, who finished eighth in the individual 200m in Beijing, tested positive for several anabolic steroids, including stanozolol. The IOC stores samples for a decade to test with newer methods or for new substances. The ruling body conducted targeted retests before the Rio Olympics. REUTERS/Kai Pfaffenbach

Russia's Tatyana Lysenko was stripped of her London 2012 Olympic gold medal in the hammer throw after the former world champion tested positive for steroids in re-tests of her sample, the IOC said in October 2016. Lysenko tested positive for the prohibited substance dehydrochlormethyltestosterone (turinabol). REUTERS/Kai Pfaffenbach

Yuliya Zaripova was stripped of the gold medal she won in the women's 3,000 meters steeplechase at the 2012 London Olympics, the IOC said in November 2016. Zaripova, who tested positive for turinabol, had been widely expected to lose the medal after she was banned for two-and-a-half years by Russian anti-doping agency RUSADA in January 2015 after her biological passport showed abnormalities. REUTERS/Phil Noble

Russian Sergey Kirdyapkin was stripped of the 50-km walk gold medal he won at the 2012 London Olympics after the Court of Arbitration for Sport upheld an appeal by the IAAF against the Russian anti-doping agency RUSADA. REUTERS/Luke Macgregor

Russia's Mariya Savinova-Farnosova was stripped of her 800m London 2012 Olympic Games gold medal after the Court of Arbitration for Sport in February 2017 imposed a four-year ban, saying there was "clear evidence" she used performance-enhancing drugs. REUTERS/Fabrizio Bensch

Double-gold-winning bobsledder Alexander Zubkov was stripped of his two golds by the IOC in 2017 and banned from the Olympics for life because of doping violations. REUTERS/Murad Sezer

Russian bobsledder Alexey Voevoda (L) was given a life ban from the Olympics for anti-doping violations at the 2014 Sochi Winter Olympics where he won two gold medals. Previously, Alexander Zubkov (R), Voevoda's teammate in both events, was also found guilty of anti-doping violations and disqualified. REUTERS/David Gray