(Reuters) - China will be seeking to avoid a repeat of the drugs scandals that have become a regular feature of sports competitions when the Beijing Olympics open on August 8.
But two of its own athletes have been banned for life for doping offences in the past month, dealing an embarrassing blow to the host nation in the run-up to the Games.
Here is a timeline showing some other major doping scandals that have seen Chinese athletes banned and/or stripped of medals over the last 14 years.
* 1994: Seven swimmers and four other athletes test positive for dihydrotestosterone at the Asian Games in Hiroshima. China stripped of nine of its 23 gold medals.
* January 1998: Four Chinese swimmers fail pre-competition doping tests for the diuretic triamterene before swimming world championships in Perth.
-- Yuan Yuan, and her coach, Zhou Zhewen, disqualified from the championships after being caught with 13 vials of muscle-building human growth hormone (HGH) at Sydney airport. Zhou banned for 15 years, Yuan for four years.
-- Chinese Olympic Committee (COC) punished 24 athletes and coaches for doping or handing out banned drugs.
* 1999: Ten swimmers and swimming coaches suspended for doping offences, some for the second time.
* 2000: Controversial coach Ma Junren and six of his distance runners dropped from China team before the Sydney Olympics after blood tests showed abnormal results.
-- Twenty one other athletes -- including four swimmers -- cut from China team after “suspicious” test results.
* July 2001: Women runners Liquing Song and Lili Yin, who trained under Ma Junren, banned for two years after testing positive for testosterone the previous year. Male race walker Yunfeng Lui also banned for two years.
-- October - Women weightlifters Yang Xuewei and Qiu Xiexion banned for two years for doping.
-- November - Two women weightlifters and a boxer among 11 tested positive for banned substances at the National Games. A swimmer and three field athletes pulled out of competition after blood tests showed abnormal results.
* 2003: COC said 16 athletes from nine sports -- including Beijing Hyundai soccer player Zhang Shuai -- failed tests and received bans from six months to three years.
-- Swimmer Li Ning suspended for two years, her coach, Liu Guangtan, banned for life, after a positive test for banned steroid testosterone.
* October 17, 2005: Distance runner and Olympic medal hopeful Sun Yingjie lost medal and received two year ban for positive test for steroid androsterone at National Games in Nanjing.
-- December A local court found her innocent after training partner admitted spiking her drink, but authorities refused to lift ban.
* October 2007: Asian Games triathlon gold medalist Wang Hongni banned for two years, meaning she will miss Olympics, after failing out-of-competition doping test.
* June 27, 2008: China’s top backstroke swimmer, 25-year-old Ouyang Kunpeng, and his coach Feng Shangbao are both banned for life after positive test for an illegal substance.
* July 2, 2008: Wrestler Luo Meng and his coach Zhang Hua handed lifetime bans after positive test for a banned diuretic.
Source: Reuters. Compiled by Nick Mulvenney and Gillian Murdoch