Trainer Gerard Butler was disqualified for five years by the British Horseracing Authority (BHA) on Wednesday after nine horses in his care tested positive for the banned anabolic steroid stanozolol.
Irishman Butler, based in Newmarket, England, admitted injecting horses with a product for injured joints and faced seven charges of breaching the Rules of Racing.
A BHA disciplinary panel said Butler administered the prohibited substance Rexogin which contains stanozolol – the steroid used by disgraced Olympic sprinter Ben Johnson at the 1988 Seoul Olympics – to four horses using a method restricted by law to qualified veterinary surgeons.
The Cambridge Road trainer admitted to seven charges against him relating to samples of an anabolic steroid found in horses in his care.
Nine horses produced positive samples, five cases of which were identified as the joint treatment Sungate, which contains the banned anabolic steroid stanozolol.
Adam Brickell, the BHA's director of integrity, legal and risk said: "BHA's position, which was upheld by the disciplinary panel, was that the most serious charges related to Gerard Butler's gross failure to look after the best interests of four horses in his care," Brickell said.
"The gravity of the breaches escalated when Butler finally provided evidence as to where he had purchased the drug in question and admitted that the product he had administered himself to four horses was not the equine veterinary product Sungate, but instead an unlicensed stanozolol-based product called Rexogin, manufactured for use in humans."
Butler said on Wednesday: "I would like to spend the day composing myself and considering a response. I plan to issue a statement tomorrow afternoon.
"I watched my mother sign a card and put it on my brother's coffin. To get through this we will need a fraction of the strength that she needed to do that."
His ban will begin tomorrow and run until December 4 2018.