Maria Sharapova revealed on Monday night that she has tested positive for a banned substance called meldonium, having taken the drug knowingly for the past decade.

The Russian tennis star had taken meldonium to help with her ill health, having first been advised to take the drug by a family-approved doctor in 2006 when it was not on the World anti-doping agency’s banned substances list.

However, Wada outlawed meldonium on 1 January 2016 and informed all athletes via email of the changes for the year, which Sharapova admitted neither her nor her team had checked before the Australian Open this year.

The International Tennis Federation [ITF] confirmed that Sharapova failed the drug test on the same day as her quarter-final defeat by Serena Williams in Melbourne, and she was informed of the failed test via letter last week.

Meldonium is a metabolic modulator that aids blood flow and is used to treat patients suffering from heart failure and cardiac issues. While it is used to treat cardiac and vascular diseases, it was found to have a positive influence on healthy athletes given it can increase endurance and aerobic capabilities, with Wada finding evidence that it had been abused for that purpose.

Maria Sharapova's career defining moments Show all 25 1 /25 Maria Sharapova's career defining moments Maria Sharapova's career defining moments 19 April 2001 Makes professional debut at the age of 14 2001 Getty Images Maria Sharapova's career defining moments 14 January 2003 Makes Grand Slam debut at Australian Open 2003 Getty Images Maria Sharapova's career defining moments 3 July 2004 Wins first Grand Slam title at Wimbledon at age of 17 2004 Getty Images Maria Sharapova's career defining moments 22 August 2005 Ranked world No 1 for the first time 2005 AFP Maria Sharapova's career defining moments March 2006 Forbes names Sharapova the highest-paid female athlete in the world 2006 Getty Images Maria Sharapova's career defining moments 10 September 2006 Wins the US Open by beating Justine Henin 2006 Getty Images Maria Sharapova's career defining moments 27 January 2008 Wins the Australian Open without dropping a set 2008 AFP Maria Sharapova's career defining moments August 2008 Long-standing shoulder injury requires surgery, forcing Sharapova to miss the 2008 Olympics 2010 AFP Maria Sharapova's career defining moments 14 January 2010 Launches the Nike Maria Sharapova Collection after the success of the 'Little Black Dress' from the 2006 US Open. 2006 Getty Images Maria Sharapova's career defining moments January 2011 Splits with coach Michael Joyce, appoints Thomas Hogstedt 2009 Getty Images Maria Sharapova's career defining moments January 2012 Ends engagement to Slovenian professional basketball player Sasha Vujacic after three-year relationship BURAK KARA Maria Sharapova's career defining moments 10 June 2012 Completes career Grand Slam after winning the French Open 2012 AFP Maria Sharapova's career defining moments June 2012 Named the 15th highest-paid athlete in the world by Forbes 2012 Getty Images Maria Sharapova's career defining moments 5 August 2012 Wins Olympic silver medal at London 2012 after losing to Serena Williams in final 2012 AFP Maria Sharapova's career defining moments 11 January 2013 Global launch of Sugarpova sweets line alongside Jeff Rubin 2013 Getty Images Maria Sharapova's career defining moments September 2013 Considers changing her name to Maria Sugarpova for the US Open but decides against it 2013 AFP Maria Sharapova's career defining moments September 2013 Third shoulder injury ends her season prematurely 2013 AFP Maria Sharapova's career defining moments 7 June 2014 Wins second French Open title by defeating Simona Halep 2014 Getty Images Maria Sharapova's career defining moments July 2015 Splits up with boyfriend and fellow tennis professional Grigor Dimitrov 2014 Getty Images Maria Sharapova's career defining moments 26 January 2016 Knocked out in Australian Open quarter-finals by Serena Williams and doesn’t play again due to injury 2016 Getty Images Maria Sharapova's career defining moments February 2016 Announces deal to make Sugarpova Premium Chocolates with Polish company Baron Chocolatier to be released in May this year Getty Images Maria Sharapova's career defining moments 7 February 2016 Sharapova reveals she has failed a drug test after testing positive for the banned substance meldonium, with the ITF provisionally suspending her from 12 March. 2016 Getty Images Maria Sharapova's career defining moments 8 June 2016 Sharapova is given a two-year ban by the ITF for her positive drugs test. AFP/Getty Maria Sharapova's career defining moments October 2016 Sharapova's ban is reduced from two years to 15 months on appeal. Getty Maria Sharapova's career defining moments 26 April 2017 After serving her ban, Sharapova made her return to professional tennis at the Porsche Grand Prix in Stuttgart, defeating Roberta Vinci. Getty

Despite taking meldonium for a decade, Sharapova will only be deemed to have been breaking Wada’s regulations since it was banned at the start of the year, though she did compete with the substance in her body at the Australian Open in January.

Sharapova fails drug test

Sharapova has not played since her quarter-final exit in Melbourne, having been replaced in Russia’s Fed Cup team and withdrawn from the BNP Paribas Open at Indian Wells in order to fully recover from an injury to her left forearm, which she confirmed is still hampering her.