Junior Dos Santos’ flagged drug test was due to a diuretic, a representative for the former UFC heavyweight champion today revealed.

A statement sent to MMAjunkie by Dos Santos rep Ana Claudia Guedes identifies Hydrochlorothiazide – which is typically used to prevent high blood pressure, according to WebMD.com – as the culprit, and states that team is currently seeking to discover how the substance made it into the Brazilian slugger’s system.

Junior tested positive for a substance called Hydrochlorothiazide, which is a diuretic and is banned by USADA due to its use as a masking agent. We do not know where this substance came from. Junior has had his blood and urine randomnly tested many times and has never once tested positive for a banned substance.

We requested testing of his B sample today. Most times, the B sample will show the identical results as the A sample. Therefore, we are already working on analyzing his nutritional supplements and medications to determine whether anything might have been contaminated. Jeff Novitzky and Donna Marcolini of the UFC have provided the guidance for this process, and we are grateful to them for their professionalism and competence.

Earlier today, UFC officials announced that Dos Santos (18-5 MMA, 12-4 UFC) had been pulled from a planned UFC 215 fight with Francis Ngannou (10-1 MMA, 5-0 UFC) due to a potential doping violation stemming from an Aug. 10 out-of-competition test administered by the U.S. Anti-Doping Agency, the UFC’s official anti-doping program administrator.

Ngannou initially vented his frustration at losing the high-profile fight, but Dos Santos’ rep said the two have since spoken and cleared the air.

Junior remains committed to and supportive of USADA drug testing – even if he is bearing an unfortunate consequence of it. He spoke personally with Francis Ngannou and apologized for the unintended consequence to him. Junior thanks Francis for the sympathy, understanding, and respect that transpired during their call, and very much looks forward to resolving this situation so that he and Francis can set up a new date to face one another.

Featuring a pair of championship matchups, UFC 215 takes place Sept. 9 at Rogers Place in Edmonton, Alberta, Canada. The night’s main card airs on pay-per-view following prelims on FS1 and UFC Fight Pass.

For more on UFC 215, check out the UFC Rumors section of the site.

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