Greek sprinter Tassos Gousis is the first athlete to be officially sent home from the Olympic Games in Beijing after a positive drugs test.
Gousis failed a Greek doping agency test and was ordered to return home from his training camp in Japan.
The International Olympic Committee confirmed the positive test was done since it officially took over drugs testing for the Games on July 27.
But it said it had not conducted the test itself and so the case was one for the Greek authorities to deal with.
Gousis now risks being banned from the London 2012 Olympics as well under a new IOC rule that states all athletes with a suspension of more than six months are to be banned from the next Olympics as well.