The World Anti-Doping Agency (WADA) is looking into allegations made by a former Chinese physician that athletes in his country benefited from systematic doping in the 1980s and 90s.
Former Olympic team doctor Xue Yinxian, 79, who is requesting political asylum in Germany, claimed that more than 10,000 athletes aged as young as 11 were introduced to a compulsory doping structure.
"In the 1980s and 90s, Chinese athletes on the national teams made extensive use of doping substances," Xue told the German broadcaster ARD.
"Medals were tainted by doping – gold, silver and bronze. There must have been more than 10,000 people involved. People believed only in doping, anyone who took doping substances was seen to be defending the country. All international medals [won by Chinese athletes in that time] should be taken back."
The doctor claims that athletes across sports including football, volleyball, basketball, table tennis, badminton, athletics, swimming, diving, gymnastics and weightlifting were all involved.
Due to the statute of limitations having long passed, there is no chance of removing the medals won during the period.
"Grandma is home"
According to Xue, Chinese athletes were repeatedly tested until they came back negative, then they were sent to international competitions.
"Grandma is home" was the call sign applied to those athletes who no longer had identifiable traces of doping in their bodies.
In the interview with ARD, Xue suggested that the system may have continued after she was sacked from the national team after declining to give a young gymnast a banned substance at the 1988 Olympics in Seoul.
"If you refused to dope, you had to leave the team,” she said. "At first, the youth-age group teams used the substances – the youngest were 11 years old.
"I couldn’t do anything about it."
Xue, who worked as a doctor with several national Chinese teams in the 1970s and 80s, fled China with her son after she first spoke out against doping in 2012.
She said she no longer felt safe in Beijing.
According to the doctor, the Chinese government tried to intimidate her by parking police cars outside her home.
She claims that she was visited in her Beijing apartment by government officials who warned her against talking about doping.
According to the ARD, they tried to contact the Chinese Olympic Committee and China's Ministry of Sport for a response to the claims, but were unable to receive a reply.
WADA to investigate the claims
In a statement, WADA said it will investigate Xue's claims, but also pointed out that it would be quite difficult to prosecute cases that are at least 30 years old.
The WADA code, which harmonises anti-doping policies across global sport, was only introduced in 2003.
"As a first step, the agency has asked its independent intelligence and investigations team to initiate an investigative process in order to collect and analyze available information in co-ordination with external partners," read the statement.
Earlier this month, China was among the nine countries suspended from weightlifting for a year after drug tests came back positive.