Taiwanese weightlifter Chen Po-pu became the first athlete to be sent home from Sydney after testing positive to steroids.
News of his expulsion was followed by confirmation that Bulgarian long and triple jumper Iva Prandzheva, a two-time world outdoor championship medallist, had failed a second test for anabolic steroids.
Later on Wednesday Kazak swimmer Yevgenia Yermakova was barred from the Games for testing positive to furosemide, a diuretic.
Chen, who took silver and bronze medals at world junior competitions in 1997 and 1998, had been due to compete in the 62 kg category but was expected to leave Sydney at the earliest opportunity.
Chinese Taipei Weightlifting Federation (CTWF) chairman Chang Chou-kuo said that Chen tested positive in a test taken by the International Weightlifting Federation on August 28th.
Prandzheva (28), who won silver and bronze in the triple jump at the 1995 and 1993 world championships respectively, tested positive for the banned steroid nandrolone and was immediately suspended by her national federation, according to Giorgio Reineri, spokesman for the IAAF.
The drug turned up after a test at the London Grand Prix on August 5th and a B test is scheduled for September 20th.
"If the B test confirms the first we will put her case to the IAAF's arbitration committee," said Dobromir Karamarinov, general secretary of the Bulgarian Athletics Federation, adding that he believed that would only happen after the Sydney Games.
The athlete was not included in the Bulgarian party that arrived in the Olympic city earlier this month. She had previously tested positive for steroids at the Atlanta Olympics, where she was fourth in the triple jump and seventh in the long jump.
Yermakova returned a positive test for furosemide following a meeting in Monaco in May, the sport's international governing body, FINA, said in a letter to the International Olympic Committee.
Yermakova (24), formerly represented the Soviet Union and was a finalist in the 50 and 100 metres freestyle at the 1991 world championships before swimming for Kazakhstan at the Atlanta Games.
Officials are hoping Sydney will be the cleanest Games on record and expect to test 400 athletes.
