The International Association of Athletics Federations (IAAF) has annulled all sprinter Marion Jones's results dating back to September 2000.
Thanou (right) may get the gold medal returned by Jones
Athletes who finished behind sprinter Jones at the 2000 Olympics are now set to move up the finishing order.
She won five medals, including three golds, in Sydney but they will be re-allocated by the International Olympic Committee next month.
Jones is to serve a two-year ban after admitting she used steroids.
She won gold medals in the 100m, 200m and 4x400m relay in Sydney along with bronze medals in the long jump and 4x100m relay, becoming the first woman to win five medals at a single Olympics.
An IAAF statement said Jones's ban, which will last until 7 October 2009, by which time she will be almost 35, also required "the forfeiture and return of all awards and medals" obtained from September 2000 onwards, along with all the prize money.
The federation has also recommended that the other members of the relay teams be stripped of their medals.
Gold and silver medals won by Jones at the 2001 World Championships in Edmonton will also no longer be recognised as a result of the IAAF ruling.
The IOC, meanwhile, now has to decide if Katerina Thanou should be awarded a gold medal.
The Greek sprinter finished second to Jones in the 100m in Sydney, but was herself banned for two years after failing to appear for a drugs test at the 2004 Athens Olympics.
Jamaica's Tanya Lawrence took the bronze medal in the 100m in Sydney behind Jones and Thanou.
Jamaican Merlene Ottey was fourth in the race and is now in line for a medal.
Pauline Davis-Thompson is set to swap her silver medal for a gold having finished second to Jones in the 200m.
Susanthika Jayasinghe of Sri Lanka and Jamaican Beverly McDonald finished third and fourth respectively.
The IOC has still to decide whether to accept the IAAF's recommendation to strip the other US relay athletes of their medals.
But the United States Olympic Committee say they will abide by the IOC's decision on relay medals and not appeal.
Jamaica, Russia and Nigeria followed behind the United States in the women's 4x400m relay, while the American team edged out France to finish third in the 4x100m relay.