Henderson successfully defended his 155-pound title for the second time, defeating Diaz via unanimous decision in the headlining fight of the UFC on Fox event at KeyArena in Seattle.
Henderson declined to answer directly in an immediate postfight interview when asked whether he had a toothpick in his mouth during the fight. Asked again at a news conference later that night, Henderson admitted he regularly trains that way.
"I cannot confirm or deny that," Henderson said with a smirk. "I normally do, yeah. I have it in practice (and) when I spar. It's a bad habit, but whatever. I've gotten away with it so far."
Internet videos that later surfaced confirmed the presence of what appeared to be a toothpick sticking out of Henderson's mouth at the conclusion of the fight.
UFC president Dana White stated he saw a toothpick in Henderson's mouth in between rounds.
"Let me tell you what, I saw a toothpick pop out of his mouth when he walked back to the corner," White said during a postfight interview on Fuel TV. "That is the craziest thing I have ever seen. That is so not legal it's not even funny."
White added he did not expect Henderson to receive any punishment.
The Washington State Department of Licensing issued a statement saying that it does not plan on investigating the incident.
"The Department will not be investigating the alleged toothpick incident," the statement said. "We do not have any rules in Washington that specifically address a toothpick in a fighter's mouth. However, we're here to protect the safety and welfare of the participants, so we will be having discussions moving forward about this topic."
Representatives from Henderson's camp declined to comment further when reached Saturday night.
Mixed martial artists are searched prior to competing, including the mouth area. Officials also verify that contestants wear a mouthpiece.
Diaz, when asked for his thoughts on the toothpick at the news conference, gave a long, puzzled stare across the podium toward Henderson before responding.
"I don't know if he did, but that's weird," Diaz said.