The managing owner of top Tasmanian stayer Eastender has given an assurance that nothing was administered to the horse before Monday's Adelaide Cup.
Eastender was withdrawn by stewards a few hours before the race after a routine stable inspection.
Chief steward Johan Petzer said that stewards "were concerned with some raceday treatment practices in relation to Eastender" and ordered the horse be scratched to "protect the integrity of racing."
However owner Denise Martin, one of Australia's leading syndicators based in Sydney, said all owners were totally satisfied nothing untoward had taken place and trainer Barry Campbell had their full support.
"The owners, all 13 of them, are 110 per cent behind our trainer," she said.
"Nothing was administered to the horse."
Martin said she didn't know whether anything had been found on the premises where Eastender was temporarily stabled and that would be up to the stewards to clarify at an appropriate time.
"The owners are upset and feel for Barry (Campbell) but no-one has 'gone to ground' as some people are suggesting," she said.
"Barry couldn't be contacted because the stewards took his phone and I was in transit from Adelaide to Sydney."
Martin said although everyone was disappointed that Eastender couldn't take his place in the field, he would have faced a difficult task had he started.
"As it turned out, it was a slowly-run race and it would have been hard for him to come from the back of the field carrying 58kg," she said.
Martin said Eastender would be returning to Tasmania on Wednesday for a short break but his all-conquering season - including wins in the Devonport, Hobart and Launceston Cups - was not over.
"He'll have a nice two-week rest at Armidale Stud then Barry will get him ready for a race in Melbourne leading up to the Andrew Ramsden (at Flemington on May 25)," the owner said.
The $400,000 Andrew Ramsden over 2800m gives the winner automatic entry into the Melbourne Cup.