Russian tennis star Maria Sharapova isn't competing at the 2016 Olympics. At a March 7 press conference in Los Angeles, she told reporters she'd tested positive for meldonium, a prescription heart drug that improves blood flow. It was banned in January by the World Anti-Doping Agency. Robyn Beck/AFP/Getty Images hide caption

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Olympic Athletes Still Use Some Rx Drugs As A Path To 'Legal Doping'

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Justin Gatlin celebrates victory in the 100 meters at the U.S. Olympic Trials for track and field. Gatlin has been suspended twice for failing doping tests, once in 2001 and again in 2006. Andy Lyons/Getty Images hide caption

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At The U.S. Olympic Trials, Mixed Opinions About Russian Doping Scandal

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Shortly after winning this race, Tyson Gay acknowledged failing a drug test. He is believed to have used a cream provided by an anti-aging specialist whose clients include several NFL players, reports ProPublica. Fabrice Coffrini/AFP/Getty Images hide caption

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The head of the World Anti-Doping Agency calls Lance Armstrong's lifetime ban "done and dusted." Armstrong is seen here riding in an event in Iowa this year. Matthew Stockman/Getty Images hide caption

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American cyclist Chris Horner celebrates winning Spain's Vuelta bicycle race Sunday. Anti-doping officials say that Horner, who at 41 is the oldest ever to win one of cycling's top events, was not at the hotel drug testers visited. Jaime Reina/AFP/Getty Images hide caption

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