Olympic champ Sun Yang failed doping test in May  

File photo of Sun Yang [Photo/Xinhua]

Chinese multi-Olympic and world swimming champion Sun Yang had failed a doping test and been banned for three months, China Anti-Doping Agency (CHINADA) told Xinhua on Monday.

The star swimmer tested positive for stimulant trimetazidine on May 17 during the national championships.

Sun gave up the right to have the B sample tested but defended himself in a July hearing where the experts decided to hand him a three-month ban.

Sun said he used the prescription drug Vasorel for medical reasons and had been unaware that its substance trimetazidine was listed in WADA's 2014 prohibited list.

Trimetazidine is able to increase coronary flow reserve and was added to the prohibited list in January 2014.

"I have been tested numerous times during years of training and competition and I had never failed one before," said Sun on Monday, the Zhejiang native, who was also fined 5,000 RMB (about 816 U.S. dollars) with his national 1,500m freestyle title deprived.

"I was shocked and depressed at that time, but at the same time it made me cherish my sporting life even more. I will take it as a lesson and be more careful in the future."

The Zhejiang Swimming Association said the provincial association and some related officials were also punished by the Chinese Swimming Association.

The Chinese swimming body decided to cut Sun's ban to three months because the swimmer "proved with sufficient evidence that he did not intend to cheat," explained Zhao Jia, deputy director of CHINADA.

"But his failure to inform the doping control official should be punished all the same," he added.

Both Sun and Zhejiang team doctor Ba Zhen failed to file the therapeutic use exemption when Sun took the test. Sun had been taking Vasorel from time to time since 2008 when he started to suffer heart palpitations, according to CHINADA.

Along with Sun Yang, CHINADA also announced six other positive cases in its quarterly report on its official website.

"Sun is the most famous athlete in China and is known in the world, which means we need to handle his case very cautiously. This is huge bad news but we will not cover it up," said Zhao.

"We announce positive cases and test statistics in our quarterly reports just as WADA requires," he added.

Zhao said the Chinese agency had been burdened with heavy task -- 9,900 doping tests conducted in six months -- and spent a lot of time sorting out statistics and waiting for procedures of positive cases to close.

"That's why we did not release the reports for the second and third quarters until now," he said.

(Updated)