Tony Bellew has labelled any boxer who takes performance-enhancing drugs a "scumbag".
The 35-year-old, who takes on undisputed cruiserweight champion Oleksandr Usyk next month in Manchester, has long been an outspoken advocate for a clean sport.
Canelo Alvarez failed a routine test earlier this year testing positive for banned substance clenbuterol before going on to beat Gennady Golovkin back in September.
The Mexican claimed to have eaten contaminated meat and saw his suspension reduced to just six months, a result that left Bellew bitterly disappointed.
"I'm the first one to ostracise these drug cheats, these scumbags that are doing it," he told Love Sport Radio.
"When it came to what Canelo failed, they are genuine performance-enhancing drugs. He failed a drugs test claiming it was contaminated meat and it was clenbuterol.
"He literally would have had to eat a whole cow in one swoop and that's just not possible!"
Billy Joe Saunders saw authorities strip him of his world title after his own failed test earlier this year but while Bellew doesn't condone his fellow Brit's actions he doesn't think he intentionally attempted to break the rules.
"We look at Billy Joe recently - and are we really going to compare a nasal spray to performance-enhancing drug?" he added.
"I'm not condoning what Billy Joe has done. Whoever has given Billy Joe that knows what they have done and they need banning. Billy Joe signed up to the VADA rules and he failed a test under those rules.
"You can't sign up for something and say 'Well I'm not abiding by those rules'. But Billy Joe is a diamond of a fellow and a genuine person. Billy Joe is not a drugs cheat in my eyes.
"He is someone who, very similar to Dillian Whyte, has been unfortunate. But you can't sign up to these things and then complain when you fail."
