The International Olympic Committee will "take the necessary actions" after sprinter Tim Montgomery admitted taking drugs before the 2000 Olympics.
The disgraced former American athlete admitted he took testosterone and human growth hormone before the Sydney Games, where he won a 4x100m relay gold medal.
"I have a gold medal that I didn't get with my own ability," he said.
An IOC spokeswoman said it would look into the matter as part of its open file on the Balco investigation.
She also said the IOC supports the US Olympic Committee's call for Montgomery to voluntarily return his medal.
Montgomery never tested positive for drugs, but was banned for two years and saw his 100m world record erased after he was implicated in the Bay Area Laboratory Co-Operative (Balco) investigation.
Balco was discovered to have been supplying illegal performance-enhancing drugs to a number of high-profile athletes.
Montgomery retired from competition after the ban was imposed in 2005.
How Montgomery's admission might affect his 2000 relay team-mates - Jon Drummond, Bernard Williams, Brian Lewis, Maurice Greene and Kenneth Brokenburr - is uncertain.
Montgomery is currently in prison after being convicted of fraud and heroin trafficking.
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