Melbourne Cup-winning jockey Michelle Payne has been suspended for four weeks after failing a urine test.
Payne, who in 2015 became the first female to win the famous event, provided a sample at the Swan Hill Cup meeting in June that was found to contain the appetite suppressant Phentermine.
The 31-year-old pleaded guilty to a rule breach and her punishment took into account "the medical circumstances involved", which relate to Payne having been prescribed Phentermine last May following pancreatic surgery necessitated by a fall while racing.
"I would like to make it clear that I take full responsibility for what has happened," she said in a statement. "The onus is 100 per cent with me as a rider to know what I am taking, and the rules around it - regardless of whether it has been prescribed to me or not.
"I regret not seeking more guidance and making certain that any treatment would lead to a breach of the rules and why we are here today. I wasn't thorough and that is completely my fault.
"My sincere apologies to everyone that this has happened in the manner that it has."
Payne recently rode at Royal Ascot, where she finished fifth on board Kaspersky in the Queen Anne Stakes.