Leading Victorian trainer Darren Weir has been fined $7000 over a positive swab returned by one of his horses after a race win.
The Weir-trained Doing Our Best tested positive to the banned diuretic frusemide in a urine sample after winning a maiden at Ballarat in February.
Weir pleaded guilty to a breach racing's rules at a hearing in front of the Racing Appeals and Disciplinary Board in Melbourne on Thursday.
Doing Our Best was also disqualified from its win.
Weir is leading the overall Victorian premiership this season with more than 150 wins.