In perhaps the biggest doping scandal of all times, cyclist Lance Armstrong admitted to doping for a period of ten years which led to him losing seven Tour de France titles.
Osayemi Oludamola of Nigeria had tested positive for a banned stimulant, Methylhexanamine. She won the 100 m sprint at the 2010 Commonwealth Games but was stripped of her title following the doping incident.
Jamaican sprinter Asafa Powell was tested positive for the stimulant oxilofrone at the national championships last month.
Former Argentina footballer Diego Maradona was suspended by FIFA after failing a drug test in 1994.
Former double sprint world champion Tyson Gay was notified by the US Anti-Doping Agency (USADA) on Friday that his A sample from an out-of-competition test on May 16 had been recorded positive. Gay said he had tested positive for a substance he could not identify and was pulling out of next month's world championships in Moscow. (Reuters)
Legendary spinner Shane Warne was sent back home midway through the 2003 World Cup after failing a drug test. Here, he goes through Singapore's Changio Airport to catch a flight back to Australia.
Indian athletes Ashwini Akkunji, Mandeep Kaur, Sini Jose, Juana Murmu, Priyanka Panwar and Tiana Mary Thomas were handed a two-year ban by the Court of Arbitration in December 2011 for using performance enhancing drugs.
Sprinter Ben Johnson of Canada, who set consecutive 100 metres world records at the 1987 World Championships in Athletics and the 1988 Summer Olympics, was tested positive for the steroid stanozolol.
American Track and Field athlete Marion Jones was accused of taking performance-enhancing drugs back in the 2000 Summer Olympics. The triple Olympic champion Jones announced her retirement from athletics after pleading guilty in 2007.
Justin Gatlin of USA was subjected to a four-year ban after testing positive for a banned substance. He came under the scrutiny twice, once in 2001 and then in 2006.