Kentucky Derby winner Medina Spirit has tested positive for the steroid Bethamehasone.
The horse faces a possible disqualification from the May 1 race at Churchill Downs and trainer Bob Baffert has been suspended from entering horses at the Louisville track, pending an investigation by the Kentucky Horse Commission.
The horse had 21 picograms in its system, the legal limit is 10.
Baffert has insisted on his innocence.