Nate Diaz accused Conor McGregor and the rest of the UFC of using performance enhancing drugs as the two traded verbal jabs throughout their UFC 196 press conference promoting their March 5 fight.

“They’re all on steroids! Everybody,” Diaz said.

When asked to clarify his comments a few minutes later, Diaz doubled down on his statements. He even called out specific fighters, accusing Rafael dos Anjos and Anthony Pettis of using PEDs.

Diaz replaced dos Anjos in the March 5 fight after the lightweight champ suffered a broken foot. Dos Anjos defeated Diaz in December 2014, and beat Pettis a few months later. Pettis was considered among the possible replacements when it was revealed McGregor would need a new opponent.

McGregor was supposed to move up from 145 pounds to 155 pounds for his fight with dos Anjos, but he’ll be making the leap to 170 pounds now that he’s facing Diaz. Despite going from a featherweight to the lightweight division in less than three months, the UFC’s most popular fighter adamantly denied Diaz’s claim.

“Steroids? Man, what are you talking about, steroids?” McGregor asked. “Don’t be putting my name with steroids. I’m major against that. Don’t put my name and the name of steroids’ name. The only weight I give a [expletive] about is the weight of them checks. And my checks are always super-heavyweight. So I don’t give a [expletive].”

We present to you, 'The Best Of: Conor McGregor vs. Nate Diaz UFC 196 Press Conference'. Enjoy!

Posted by UFC on FOX on Wednesday, February 24, 2016

Diaz is known for being a trash talker, and he did his best to cause a stir by making such controversial claims. McGregor pointed out that two of Diaz’s teammates have been caught cheating. But while every top fighter isn’t on steroids, UFC has certainly had its issues with PEDs.

Anderson Silva, arguably the greatest MMA fighter of all time, has failed multiple drug tests. He defeated Nate Diaz’s brother, Nick Diaz, in his last fight on Jan. 31, 2015, but the decision was overturned to a “no contest,” and the Nevada State Athletic Commission suspended him for a year. Silva has remained adamant that he didn’t knowingly take steroids, and he returns to the octagon Saturday against Michal Bisping.

Other big names such as Chael Sonnen and Vitor Belfort have been caught using PEDs in recent years. After his suspension in 2014, Sonnen said he thought he could get away with cheating because he didn’t think he would be tested with more than a month remaining until his fight.

“I was hit on a surprise test that was 44 days before a fight. Generally in our business we’re tested fight night, so whatever it is you’re doing or you’re not doing, you gotta show up clean on fight day,” Sonnen said on Chris Jericho’s “Talk is Jericho” Podcast.

“I knew it. I didn’t think I’d be tested for another 44 days. I tried to game the system.”

Donald Cerrone, who was considered a possible replacement for dos Anjos, said rumors he failed a drug test are fabricated. Cerrone accused dos Anjos of using steroids before their fight in December, but he claims his comments were made in jest.

UFC President Dana White responded to Diaz’s comments, telling TMZ the company has the best drug testing program in all of sports.