Park Tae-Hwan's agency have confirmed that the South Korean Olympic gold medallist has failed a drugs test.
The 25-year-old's representatives Team GMP have claimed that the swimmer, known as 'Marine Boy', tested positive for a banned substance that was administered by a doctor.
"As a world-class swimmer, Park Tae-Hwan has been extremely careful about what he takes and he hasn't even taken cold medicine so that he wouldn't fail doping tests," Yonhap News Agency quotes Team GMP as saying.
"At the time, the hospital offered to give Park an injection and he repeatedly asked if it contained any illegal substances. The doctor said there would be no problem, yet it turned out the injection contained a banned substance."
Park won gold in the 400m freestyle final at the Beijing Olympic Games in 2008 and came away with two silvers at London 2012.
