Many athletes have confessed to using performance enhancing drugs during their careers, but some will go to extreme lengths to deny the claims.
In the last two days, tennis star Sara Errani blamed her mum's tortellini, and it has been claimed that racehorses are failing drug tests because their grooms are urinating in stables.
Both of those unique explanations join this list of some of the best doping excuses ever.
'I kissed a girl with cocaine in her mouth'
In 2009, French tennis player Richard Gasquet tested positive for cocaine but said he didn't knowingly consume it.
The former world no. 7 claimed he kissed a girl in a Miami nightclub who had used the drug, and said she must have had some powder in her mouth.
It was later found that "the cocaine entered his system through inadvertent contamination in a nightclub", and he was suspended for two-and-a-half months.
'Waiter, there's something in my steak'
Three-time Tour de France winner Alberto Contador tested positive for Clenbuterol.
Clenbuterol is used to increase muscle mass in animals and the Spaniard said he must have eaten some meat which had been injected with the drug.
Contador was banned for two years as a result of the positive test.
'The victim of sabotage'
In 2006 Justin Gatlin tested positive for testosterone. His camp claimed he was the victim of sabotage by a hostile masseur, who rubbed a cream containing the banned substance into his legs.
His coach Trevor Graham argued that the masseur held a grudge against the former Olympic champion.
Gatlin had his eight-year ban reduced to four on appeal.
'My mum gave it to me'
Australian cricket great Shane Warne tested positive for a diuretic in 2003, just days before the start of the Cricket World Cup.
Warne said he took what he thought was a fluid tablet, which was to help improve his appearance. The tablet was given to him by his mother.
The leg-spinner claimed he was the victim of anti-doping hysteria after the incident.
He was ultimately suspended for 12 months by the Australian Cricket Board.
'It was my unborn twin'
In 2004, cyclist Tyler Hamilton was found to have someone else's blood cells in his blood after a test conducted by the US anti-doping agency.
Hamilton claimed this was because he had absorbed his unborn twin, which died in his mother's womb.
The American was suspended for two years and later confessed to doping in a book he wrote, but not with anybody else's blood.
He also said scientists came up with the "vanishing twin" alibi.