High-profile drugs cases in Tennis
British number three Dan Evans has announced he tested positive for cocaine in April.
Here, Press Association Sport looks at other high-profile doping cases in tennis.
Frenchman Gasquet tested positive for cocaine in 2009 and was banned for 12 months by the International Tennis Federation (ITF). He took his case to the Court of Arbitration for Sport and successfully argued he had ingested the substance inadvertently after kissing a woman in a nightclub. He was cleared of any wrongdoing.
Former Wimbledon champion Hingis retired in 2003 at the age of 22. She returned to tennis two years later only for her comeback to be ended in 2007 by a positive test for a metabolite of cocaine at Wimbledon. She was suspended from tennis for two years but made another comeback in 2013 and has become a grand slam-winning doubles specialist.
Sharapova shocked the sporting world by announcing she failed a drugs test at last year's Australian Open. She was handed a two-year suspension by the ITF - later reduced to 15 months - for committing an anti-doping violation. The five-time grand slam champion tested positive for prohibited substance meldonium.
The Croatian was given a nine-month ban in 2013 after the ITF said traces of banned stimulant nikethamide were found in a sample he gave at a tournament in Munich. Cilic claimed the failed test was a result of taking over-the-counter glucose tablets, and argued only a by-product of the banned substance had been found. He took his case to CAS and the ban was reduced to four months. Cilic won his first grand slam title at the US Open the following year.
Another controversial case. Troicki refused to take a blood test at a tournament in Monte Carlo in 2013, claiming he was feeling unwell and had a phobia of needles. He was banned for 18 months, reduced to 12 months on appeal to CAS. Troicki maintained his innocence, claiming he had been told by the doping control officer he could take the test the following day. Novak Djokovic spoke out in defence of his friend, calling it an injustice and claiming he had lost faith in the system.
Agassi made the shocking revelation in his post-retirement autobiography that he failed a test in 1997 after taking crystal meth and then lied to tennis authorities to escape punishment. He told the ATP in a letter he had taken the drug accidentally. The governing body believed him and the failed test remained a secret for the rest of Agassi's playing career.
The former British number one was among a number of players to test positive for the steroid nandrolone in 2003. He was cleared of wrongdoing after a tribunal ruled he, along with the other players, had taken the drug inadvertently in contaminated pills handed out by ATP trainers.
In March 2010, the American pleaded guilty to importing human growth hormone into Australia and was suspended for two years. The ban was reduced to one year after the ITF said he had fully cooperated with its investigations. Odesnik was banned for 15 years in March 2015 after a second offence, this time testing positive for a number of banned substances, including steroids.