The Brazilian MMA Athletic Commission has fined and suspended Rony Jason after his test from UFC Fight Night 67 came back positive for a banned substance.

According to a report by MMAFighting.com, Jason was found to have diuretic hydrochlorothiazide in his system after his victory over Damon Jackson. The result has been changed to a no-contest, with Jason receiving a nine-month suspension. He is also likely to lose the $50,000 “Performance of the Night” bonus the promotion provided him.

In a statement to the site, Jason denied any wrongdoing.

“I’m talking to my nutritionist and UFC doctors,” Jason said. “The only thing I used on the day of the weigh-in was vitamin C, so we’re checking if any of the medication I used for my ankle injury has something to do with it.”

All 23 of the other fighters who competed at the event were tested and the results came back clean.