Stephan Bonnar and Dave Herman tested positive for banned substances after their fights at UFC 153 in Brazil on Oct. 13, the promotion announced Friday.
Bonnar reportedly tested positive for Drostanolone, an anabolic steroid, while Herman was flagged for marijuana metabolites. It is the second time both fighters failed a drug test.
“The UFC has a strict, consistent policy against the use of any illegal and/or performance-enhancing drugs, stimulants or masking agents," said Zuffa LLC in a statement. Zuffa is the parent company of both UFC and Strikeforce.
UFC events in the United States are regulated by the host state's athletic commissions. But when the world's premier mixed martial arts promotion brings its events to the international scene, most of those countries do not typically test fighters.
Instead, the UFC works with an independent third party to conduct drug testing of its fighters. All 24 fighters on the card at UFC 153 were tested, the promotion told MMAJunkie.com.
Bonnar was in the main event against Brazilian native Anderson Silva, the middleweight champion, in a non-title bout fought at light heavyweight. Silva, considered the greatest pound-for-pound fighter in MMA history, won by TKO in the first round when he landed a devastating knee to Bonnar's solarplexus. Bonnar retired earlier this week before the announcement of his failed test became public.
Herman lost via submission to Antonio Rodrigo Nogueira at UFC 153.
"Both fighters have admitted taking the banned substances and have orally agreed to suspensions," Zuffa's statement continued. "Once the suspensions have been reduced to written agreements, the results of their tests and the agreed upon suspensions will be sent to the Association of Boxing Commissions official record-keeper so other jurisdictions will be on notice.”