Canelo Alvarez and Billy Joe Saunders both completed their drug testing without any adverse results.
The super-middleweight rivals clashed earlier this month with Brit Saunders pulled out by his corner after the eighth round.
He was later taken to hospital where a scan determined he had fractured his eye socket in three places.
Alvarez now holds three belts at 168lb and plans to fight the final remaining champion Caleb Plant in September in an attempt to become the undisputed champion.
And the Voluntary Anti-Doping Association (VADA) confirmed last night that both Alvarez and Saunders had passed each of their drug tests.
“Congratulations to Canelo Alvarez and Billy Joe Saunders for successfully completing Vada testing through their May 2021 bout,” read the organisation’s tweet.
Both Alvarez and Saunders have produced adverse findings in the past with the Mexican testing positive for the banned substance clenbuterol in 2018 before his rematch with Gennady Golovkin.
Alvarez was suspended for six months but blamed the result on eating contaminated meat in his homeland. He faced Golovkin following his ban and outpointed his great rival.
Later that same year, Saunders tested positive for the banned substance oxilofrine ahead of his world title clash with Demetrius Andrade.
The substance is not banned out of competition by the UK authorities but the Massachusetts commission denied Saunders a licence and he later relinquished his world title.
Saunders has barely spoken publicly since he was stopped by Canelo for his first career defeat, other than to explain how the fight ended.
“Thanks everyone for messaging,” he wrote on his Facebook page. “Broken eye socket and cheek bone in three places operation yesterday – all went well.
“You win some and lose some, didn’t feel out my league but got caught with a good shot and couldn’t see and Ben got the corner to pull it.
“Thank you all who watched I’ll be back god bless you all.”
Saunders was referring to Ben Davison, his former trainer who claimed it was he who spoke to the former champion after the eighth round.
That forced Saunders’ current coach Mark Tibbs to speak up and criticise Davison for interfering between rounds.
Few expect Saunders to return from his injuries having been inactive throughout his career.
And having lost his world titles, there appears to be few options left for the Brit. A rematch with Chris Eubank Jr tops the list but negotiations with the son-of-a-legend have been notoriously difficult.