The Irish Turf Club handed Danny Grant a two-year ban on Wednesday, with 18 months suspended because of mitigating factors.
Grant tested positive for metabolites of cocaine at the Curragh on the first day of the flat season in Ireland on March 23.
His lawyers said the source of the failed test was an herbal tea product that Grant bought online because he thought drinking it would improve his skin condition.
Grant said his skin was in bad condition because of stress.
Grant's ban starts on Dec. 9.