China's three-time Olympic champion Sun Yang has been banned for eight years for missing a doping test in September 2018, APA reports citing BBC.
The 28-year-old was initially cleared of wrongdoing by Fina, the swimming federation, in January 2019.
Following an appeal by the World Anti-Doping Agency (Wada) to the Court of Arbitration for Sport (Cas), the decision has been overturned.
An eight-year ban was imposed on Sun because this was his second offence.
He had served a three-month suspension in 2014 for taking prohibited stimulant Trimetazidine.
Sun won 200m freestyle gold at Rio 2016 having triumphed in the 400m freestyle and 1500m freestyle at London 2012.
He had told an appeal hearing in November that he missed a test because testers failed to prove their identity when they arrived at his home.
He also denied a vial containing his blood samples was smashed with a hammer.