Those wacky Diaz brothers and their marijuana, always getting into trouble!

According to Marc Raimondi of MMAFighting.com, the United States Anti-Doping Agency is looking into the fact that Nate Diaz was using a vape pen during his post-fight interviews at UFC 202. When asked, Diaz actually admitted that he was vaping CBD (cannabidiol oil).

“I can confirm that USADA is aware of the situation and is currently gathering information in order to determine the next appropriate steps,” USADA spokesperson Ryan Madden said in a statement.

Cannabidiol oil is currently banned by the UFC, but doesn’t share the same effects of traditional marijuana (THC). CBD has zero psychoactive properties and is used mostly as a medicine for pain relief, anxiety, depression, and nausea. It has also been proven effective in preventing seizures.

Diaz, who has never tested positive for any substance in his UFC career (although his brother Nick has been popped for marijuana multiple times), didn’t try to hide the vape pen or its contents.

“It’s CBD,” Diaz said. “It helps with the healing process and inflammation, stuff like that. So you want to get these for before and after the fights, training. It’ll make your life a better place.”

It’s unclear whether using immediately after the fight would be considered “out of competition” or not. Technically, the time frame for “in competition” is six hours before the fight and six hours after it, which Diaz’s vaping definitely fell into. The concerning fact might be that Diaz suggested he used before the fight as well. The UFC 202 drug test results have not been released yet.