The latest revelation of Russian doping won't be the last. National self-interest and corruption have blighted sport since the professional era began.
Calls for an independent global drug-testing agency are growing as it becomes clear many nations' procedures fall well below expected standards.
Determined to put her doping ordeal behind her, long-distance runner Lebogang Phalula has returned to running - with a spate of good results.
In a TV interview, a witness in a case against Alex Rodriguez has spoken out against the baseball player's use of banned drugs such as testosterone.
A UK newspaper says it had settled with Lance Armstrong after it was made to pay damages over a report which suggested he had used banned substances.
Sprinter Tyson Gay failed more than one drug test this year, recording one of his positives at the US championships in June.
Usain Bolt has insisted he is "clean" and that fans could trust him despite recent failed drugs test by sprint rivals Asafa Powell and Tyson Gay.
Disgraced US cyclist Lance Armstrong says that his former team overlooked allegations of doping because of a lucrative sponsorship deal.
Science is becoming the front-runner in discovering how far the human body can be pushed.
More cheats are being caught, but there are fears that the public will view the problem as endemic.
Former double world sprint champion Tyson Gay has delivered a further body blow to his troubled sport by failing an out-of-competition dope test.
Oscar Pistorius was tested for drugs before and during last year's Paralympic Games in London, says the International Paralympic Committee.
China's anti-doping head has said he was "shocked" after an anti-doping agency alleged the country produces large amounts of illegal substances.
Lance Armstrong's admission to Oprah Winfrey that he was a drugs cheat has thrown a sidelight on to the parallel endurance sport of distance running.
Lance Armstrong's confession has pushed South Africa's anti-doping body to retroactively test blood samples from over 50 top cyclists.
The International Olympic Committee has stripped American cyclist Lance Armstrong of his Sydney Olympics bronze medal, said officials.
Cyclist Lance Armstrong has spent over a decade vehemently defending himself against a litany of doping allegations. Here's a list of his denials.