On 10 May 2010, she was banned for two years by the International Judo Federation because of Clenbuterol doping and was required to give back her gold medal from the World Championships of 2009. Tong subsequently contested the ban and took her case to the Court of Arbitration for Sport which ruled that a doping violation could not be proved and found, in her favor, ordering that she be reinstated immediately with all rights. She returned to international competition in May 2011, winning gold at the Moscow Grand Slam.