Anthony Joshua says boxing "clearly has a problem" with doping after Dillian Whyte failed a voluntary drugs test and was pulled out of Saturday's all-British heavyweight contest.
Joshua, 33, will instead fight Robert Helenius at London's O2 Arena, with the 39-year-old Finn taking the fight at just a week's notice.
Asked by BBC Sport if boxing has an issue with doping, Joshua said: "I don't know how they're going to sort it out or what their solution is to this problem. But it clearly has a problem."
For the third time in 12 months, boxing is facing serious questions about the sport's credibility and its anti-doping protocols.
In October last year Conor Benn's bout with Chris Eubank Jr was cancelled in fight week after it emerged Benn had failed two voluntary drug tests. Benn has always protested his innocence, as does Whyte.
Amir Khan was banned for two years after an anti-doping test revealed the presence of a banned substance following his fight against Kell Brook in February 2022.
The case was not heard by an independent tribunal until January 2023.
On Tuesday it was confirmed Joshua would instead fight Helenius. It is the second time Joshua has had to pull an opponent from a fight due to an anti-doping violation.
In 2019 Andy Ruiz Jr stepped in on a month's notice when American Jarrell Miller tested positive for several banned substances.
Joshua has paid for extra testing by the Voluntary Anti-Doping Association for several years to go hand-in-hand with UK Anti-Doping Agency's (Ukad) testing.
In their latest report, Ukad carried out 213 in-competition tests and 133 out-of-competition tests on fighters connected to the British Boxing Board of Control (BBBoC).
However, in global boxing there is no standardisation of anti-doping rules, leading to fighters, like Joshua, choosing to insist on additional steps to provide regular testing.
But Joshua accepts not every fighter has the funds to ensure extra testing and his promoter Eddie Hearn said regular testing below the elite level of boxing is needed.
Hearn, CEO of Matchroom, has been involved with both the Whyte and Benn cases. He promotes both fighters.
Other high profile athletes to fail tests and serve suspensions include Saul 'Canelo' Alvarez in 2018 and Tyson Fury in 2015 - with both blaming the consumption of suspect meat.
Joshua, however, says he is not surprised by doping scandals in boxing.
"The thing is, people do wonder 'how long has this been going on?'.
"It makes me wonder 'how long has this situation been going on?'. In a way, I'm not shocked anymore in boxing."
The two-time world champion added: "It's not only the belt you're competing for, it's leaving this game with your faculties. Boxing is a dangerous, dangerous game. Even on the side of it where anti-doping is involved, people do take it for granted."
Hearn calls for global body to streamline testing & punishments
Conor Benn last fought in April 2022 when he stopped Chris van Heerden in two roundsWelterweight Benn failed two voluntary tests for female fertility drug clomifene before October's cancelled bout with Chris Eubank Jr.
Benn was suspended by Ukad pending their investigation before his suspension was lifted on 28 July.
The case may not be fully resolved - the body said it had 21 days to assess whether it wanted to appeal against the decision, which was taken by the independent National Anti-Doping Panel (NADP).
Benn and Whyte say they are innocent of intentional doping. Both cases, however, highlight the confusion around drugs testing in British boxing and raise questions on punishments for fighters who fail voluntary drug tests.
Both Britons returned "adverse findings" in tests carried out by the Voluntary Anti-Doping Association (Vada), but the BBBoC is guided by Ukad testing.
Matchroom and Benn were unsure if the BBBoC had jurisdiction when it came to Vada testing and so didn't immediately cancel the fight. Eubank Jr was happy to proceed with the bout, before the board's decision to unsanction the fight forced it to be cancelled two days before the event.
In Whyte's case, the fight with Joshua was cancelled immediately after Matchroom were notified by Vada.
Hearn says this was down to Joshua's refusal to fight Whyte after learning of the results at 07:00 BST on Saturday morning, but also said they had learned from the mistakes made regarding Benn's tests.
But confusion remains regarding what happens to a fighter who fails voluntary drug tests. The BBBoC argue they do have jurisdiction and suspended Benn on that basis. But an independent NADP lifted Benn's suspension after hearing the case.
The details of their decision is unknown and Ukad could yet appeal the ruling.
For a failed Ukad test, a fighter is given a two-year ban, regardless of intent - as seen with Khan's case earlier this year where the tribunal ruled out "deliberate or reckless conduct."
"Vada's a reporting agency. So from here, how does Dillian Whyte clear his name or attempt to do so?" Hearn asked.
"I don't know the answer to that. He's not licensed by the BBBoC, he's licensed by Portugal where he lives. What are they going to do about it?"
There is no global independent body that sets standards across the sport - something Hearn says needs to change.
A universal body that could oversee consistent testing, rules and punishments for doping offences.
"There are governing bodies in each state in America which have their own set of rules," he says. "The British board have rules and even that isn't clear.
"I think we need a clear set of rules for the sport globally - which is easier said than done".