Maria Sharapova told a packed media conference that she tested positive for meldonium at the Australian Open in January.
The 28-year-old confirmed that she had been taking the substance in a medicine called Mildronate for 10 years, having been prescribed it by her family doctor.
It was added to WADA's list of banned substances in January after a period of 12 months of it being monitored; because, according to a statement by the anti-doping body, of "evidence of its use by athletes with the intention of enhancing performance."
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Watch the moment Maria Sharapova revealed she failed a drugs test
Sharapova admits she made a huge mistake, and said: "I was getting sick very often and I had a deficiency in magnesium and a family history of diabetes, and there were signs of diabetes. That is one of the medications, along with others, that I received."
But what is meldonium, and have any other athletes been punished for taking it?
- Meldonium is also known as Mildronate, the name by which Sharapova knew the drug having taken it since 2006.
- It is commonly used to treat angina, other heart problems and diabetes. Sharapova referred to a family history of diabetes during her announcement.
- Meldonium was only added to the World Anti-Doping Agency's banned list from the start of 2016. However, it had been on the organisation's monitoring programme throughout 2015.
- A WADA spokesman wrote on Twitter on Monday that: "Meldonium was added to Prohibited List because of evidence of its use by athletes with the intention of enhancing performance." Studies have indicated the drug can increase an individual's capacity for physical exertion.
- The drug is manufactured by Latvian company Grindeks and widely exported to Sharapova's homeland of Russia and several neighbouring countries. However, it is not approved for use in the United States, where the tennis player has her base.
- Sharapova was the second Russian sportswoman to announce a positive test for meldonium on Monday. Figure skater Ekaterina Bobrova confirmed to Russian agency R-Sport that she had tested positive at January's European Championships, and was ruled out of the World Championships as a result.
