Cannabis is a prohibited substance in-competition in most combat sports jurisdictions, but only over a certain threshold. Only if an athlete tests positive for more than 150 ng/ml of cannabis in a sample collected in-competition will that athlete be sanctioned by the regulatory body.

Things are different in Illinois, though. The Illinois State Athletic Commission (ISAC) has a zero-tolerance policy for banned substances, including marijuana. There is no such threshold for cannabis, so if a fighter tests positive for even a small amount of the drug he or she can be suspended, fined and possibly have a win overturned.

Illinois does allow for therapuetic use exemptions (TUE) for cannabis. A request for a TUE by an athlete who uses cannabis medicinally must be made in writing. The rules for TUEs in Illinois are steep, though. An athlete would have to “experience a significant impairment to health if the prohibited substance were to be withheld.”

MMA Weekly reported Thursday that the UFC has already sent out a memo to fighters competing at UFC 225 in Chicago on June 9 about the ISAC regulations. That information would be of particular note to athletes competing Saturday at Bellator 198 in Rosemont, Ill., too.

“Because of Illinois’ no tolerance policy for marijuana, we recommend that marijuana use be discontinued for anyone participating on the UFC 225 card between now and the event,” the memo to fighters read, per MMA Weekly.

The UFC has visited jurisdictions with similar policies in the past, notably Texas. And it has affected fighters greatly. Curtis Blaydes, Niko Price and Abel Trujillo all tested positive for marijuana in relation to UFC Houston last year. Victories by Blaydes and Price were both overturned to no-contests. All three were suspended 90 days and fined $1,000. Jessica Eye famously had win over Sarah Kaufman overturned to a no-contest at UFC 166 in Houston back in 2013.

USADA, the UFC’s anti-doping partner, did not take any disciplinary action against Blaydes, Price or Trujillo, because they did not test for cannabis above the 150 ng/ml threshold.

Earlier this year, USADA suspended UFC fighter Cynthia Calvillo six months for testing positive for marijuana above that threshold in an in-competition sample collected at UFC 219 in December. She would get only a three-month ban from USADA after taking a drug course, but the Nevada Athletic Commission (NAC) suspended her longer for the violation: nine months.