Nate Diaz may have just put his foot in it this time. Following his loss to Conor McGregor at UFC 202 on Saturday night, the Stockton, California-based welterweight arrived at the post-fight press conference smoking a vape pen he explained contained a form of marijuana.

When asked by a member of the press what he was smoking, Diaz elaborated: It’s CBD. 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.”

CBD, or cannabidiol, is one of at least 113 active cannabinoids identified in marijuana. It is a major phytocannabinoid, accounting for up to 40% of the plant’s extract.

CBD is considered to have a wide scope of potential medical applications – due to clinical reports showing the lack of side effects, particularly a lack of psychoactivity, and non-interference with several psychomotor learning and psychological functions.

However, using cannabinoids in competition (six hours before and after the fight) is prohibited by the World Anti Doping Agency (WADA) Code and USADA uses WADA’s prohibited substance list. The post fight press conference that a select number of fighters were involved in, including Diaz, was within that six-hour timeframe.

Cannabis is prohibited in the UFC anti-doping policy as it’s considered a ‘specified substance’ and article 10.2.2 states: ‘The period of ineligibility shall be one year where the Anti-Doping Policy Violation involves a Specified Substance.’

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

Although Diaz’s post-fight drug test took place prior to the press conference he may have put his foot in his mouth by admitting to vaping CBD. Technically, USADA could use that admittance and sanction the punishment, which would be the same length as if he had tested positive in an actual drug test.