Mexican middleweight Julio Cesar Chavez Jnr has been fined $900,000 (£593,000) by the Nevada State Athletic Commission after testing positive for marijuana.
The 27-year-old was found to have used the drug around nine days before his unanimous points loss to WBC champion Sergio Martinez in September.
As well as the fine - which represents 30% of his purse - he has also been suspended from boxing for nine months, retroactive from the day of the fight.
The penalty is the second-largest meted out by the NSAC - dwarfed only by the $3m (£1.9m) sum Mike Tyson had to pay for biting Evander Holyfield during their 1997 clash at the MGM Grand.
In 2009, Chavez tested positive for Furosemide after his fight with Troy Rowland.