Teenage Chinese swimmer Liu Zixuan, a World Championship silver medallist this year, failed a drugs test at the National Games of China in early September.
The 17-year-old tested positive for banned diuretic hydrochlorothiazide on September 4 after finishing second in the 200 metres freestyle in a time of 1min 57.01sec before forming part of a winning 4x200m freestyle relay quartet.
She has been provisionally suspended and stripped of her result, the Chinese Anti-Doping Agency have confirmed, while the National Games Organising Committee also cancelled a sports ethics award given to her team.
Her "B" sample result is still to be heard.
Liu swam the second leg in China's silver medal winning 4x200m freestyle relay team at this year's World Championships in Budapest.
The National Games of China is a major quadrennial event held in Tianjin in August which was attended by International Olympic Committee President Thomas Bach.
Nearly 3,000 drugs tests were reportedly conducted.
Wrestlers Duan Ning and Yang Xinli also failed drugs tests and are currently waiting for the results of "B" samples.
Hydrochlorothiazide can be used as a masking agent to hide the presence of other banned substances.
Other Chinese athletes to have failed for the substance include modern pentathlete, Qian Chen, who appealed unsuccessfully to the Court of Arbitration for Sport after being stripped of her fourth place finish at Rio 2016.
Two-time Asian Games gold medallist Chen Xinyi also failed for the banned diuretic at the Rio 2016 Olympics.
It comes after a former doctor for the Chinese Olympic team, Xue Yinxian, claimed that all medals won by athletes from the country in 1980s and 1990s were achieved through a systematic doping programme existing across all sports.
An investigative process was launched by the World Anti-Doping Agency last month, but no further details have yet emerged.
Chinese swimming has a tumultuous history following a doping scandal in the 1990s after seven athletes returned positive tests at the 1994 Asian Games in Hiroshima.
China’s women came from relative obscurity to win 12 of the 16 gold medals on offer at the 1994 World Championships in Rome, prompting further speculation of systemic doping within the team.
Four years later, another four Chinese swimmers failed pre-tournament tests ahead of the 1998 World Championships in Australia.
The Asian country was subjected to further outcry when a routine check of a swimmer's bag at Sydney Airport before the event in Perth reportedly uncovered enough human growth hormone to supply the entire women’s team for the entirety of the competition.
Chinese Olympic swimming champion Sun Yang served a three month ban for failing a drugs test back in 2014.