Former Olympic champion Park Tae-hwan has been banned for 18 months due to a failed drugs test.
The South Korean tested positive for the banned substance testosterone in an out-of-competition test, which was carried out last September.
The 25-year-old won gold in the 400m freestyle in Beijing in 2008, becoming the first Korean to win an Olympic swimming medal in the process.
Park will be able to return in time to compete in the 2016 Rio Olympics.
