Legendary trainer Bob Baffert insisted he was innocent of wrongdoing on Monday in the wake of the failed drugs test against Kentucky Derby winner Medina Spirit that has left US racing in turmoil.

Medina Spirit could be only the second Kentucky Derby winner in history to be stripped of the title for doping offenses after traces of the steroid betamethasone were found in the horse's system.

It is the latest in a series of doping cases that have rocked Baffert's stable in recent years, and leaves the Hall of Fame trainer risking a lengthy ban from the sport if confirmed.

Baffert on Monday told Fox News in an interview he had never cheated, and said his immediate suspension by Churchill Downs race course on Sunday had left him a victim of "cancel culture."

Baffert told Fox that Medina Spirit had never been given betamethasone -- which is legal in US racing provided it is not administered within 14 days of competition -- and suggested the horse could have been accidentally or deliberately contaminated with the substance.

"It did not happen," Baffert told the network. "That horse has never been treated with (betamethasone). Actually, it's a legal therapeutic medicine and the amount that was in it wouldn't have any effect on the horse anyway.

"But that horse was never treated with that and so that's the disturbing part of it. I never thought I'd have to be fighting for my reputation and the poor horse's reputation.

Kentucy Derby winner Medina Spirit faces being stripped of the title after a positive doping case
Kentucy Derby winner Medina Spirit faces being stripped of the title after a positive doping case GETTY IMAGES NORTH AMERICA / Tim Nwachukwu

"We live in a new world now. These horses don't live in a bubble," he said. "They're in an open farm. People are touching them. He went from the Derby to after the Derby, everybody's out there touching them."

Kentucky racing authorities last year changed the threshold for a positive betamethasone test from 10 picograms per millilitre of plasma to 21 picograms per millilitre. A picogram is one trillionth of a gram.

"There's so many ways these horses can get contaminated and when they're testing at these really ridiculously low levels - I've been saying it for over a year now these are gonna get innocent people in trouble and this is what happened now," Baffert said.

"Bob Baffert is not stupid," the trainer added. "That is not a drug that I would use on a horse. We don't use that drug. The horse never had that in him. We have the documentation. We're going to show everything."

Baffert meanwhile said he planned to enter Medina Spirit in this weekend's Preakness Stakes at Pimlico in Baltimore, the second leg of US racing's prestigious Triple Crown.

It was not clear however if Medina Spirit would be allowed to race by the Maryland Jockey Club. The draw for the race was delayed for 24 hours until Tuesday following Sunday's doping bombshell.

Baffert meanwhile criticised Churchill Downs race track for suspending him following the drugs test revelation.

"Churchill Downs came out with that statement and that was pretty harsh," he said. "We live in a different world. This America is different. This was a cancel culture kind of thing."