Factbox

Sprinters who have been involved in doping scandals over the past 25 years:

Ben Johnson (Canada).

Stripped of his 100m gold medal at the 1988 Seoul Olympics after testing positive for banned steroids. Still the biggest scandal to hit the Olympic Games.

Katerina Thanou/Kostas Kenteris (Greece)

Thanou (100m silver medalist in Sydney) and her Greek teammate Kenteris (Sydney 200m champion) were accused of faking a motorcycle crash just before the 2004 Athens Olympics to skip a dope test. They were later given two-year bans.

Katrin Krabbe (Germany)

Double sprint champion at the 1991 world championships in Tokyo who never competed at an Olympics after a ban for the anabolic agent clenbuterol.

Linford Christie (Britain)

At 32, the oldest man to win the Olympic 100m title with victory in Barcelona in 1992. Seven years later, in semi-retirement, tested positive for the steroid nandrolone.

Dennis Mitchell (US)

The American, who won gold as part of the US 4x100m relay team at the 1992 Barcelona Olympics, was banned for two years in 1998 for excessive levels of the male sex hormone testosterone.

Merlene Ottey (Slovenia)

Jamaican-born sprinter who won world 200 titles but was banned from the 1999 Seville world athletics championships after a positive test for nandrolone. Later cleared by the IAAF.

Dwain Chambers (Britain)

Finished fourth in the 100 final at the 2000 Sydney Olympics but was banned for two years in 2003 after testing positive for the designer steroid THG in the BALCO laboratory scandal.

Tim Montgomery (US)

Also implicated in the doping scandal that engulfed the San Francisco BALCO laboratory. The American set a 100m world record of 9.78 in 2002 but later admitted to doping at the 2000 Sydney Olympics.

Marion Jones (US)

Montgomery's partner and the biggest victim of the BALCO scandal, Jones became the first woman to win five track and field medals at a single Olympics at Sydney 2000 After years of denial, she confessed to being a drugs cheat and was jailed for lying to federal investigators.

Kelli White (US)

Another BALCO victim who admitted to using a cocktail of drugs after winning the 100-200 double at the 2003 Paris world championships.

Justin Gatlin (US)

The American, who won gold in the 100 at the 2004 Athens Olympics, has served two doping bans, including four years for excessive levels of testosterone. He won 100m bronze at the 2012 London Olympics and two silvers at this year's world championships.

Veronica Campbell-Brown (Jamaica)

Twice Olympic 200m champion who is suspended after testing positive for a banned diuretic at a meeting in May this year.

Sherone Simpson (Jamaica)

Gold medalist at the 2004 Olympics in Athens and a silver medalist last year in London as part of Jamaica's 4x100m relay teams, Simpson tested positive for the banned stimulant oxilophrine at June's Jamaican athletics championships.

Asafa Powell (Jamaica)

Held the 100 world record between 2005 and 2008. Tested positive for oxilophrine at the national championships in June.

Tyson Gay (US)

Completed a memorable sweep of sprint titles at the 2007 world championships in Osaka when he won the 100 and 200 and was part of the triumphant US 4x100m relay team. Tested positive for an unidentified substance in an out-of-competition test in May this year.

Kelly-Ann Baptiste (Trinidad & Tobago)

A member of Gay's training group and 2011 world 100m bronze medalist, she withdrew from August's Moscow world championships on the opening day of competition for a doping violation.

China Daily

(China Daily 09/25/2013 page23)