Rules and fouls

In the US, and in much of the world, MMA runs on the Unified Rules of Mixed Martial Arts. They were drafted by New Jersey's athletic commission in 2000 and are kept up to date by the Association of Boxing Commissions. Some promotions abroad, like ONE Championship in Asia, use their own rules.

• Headbutts, eye gouging, biting, spitting, hair pulling, fish-hooking
• Strikes to the groin, the throat, the spine or the back of the head
• Bending fingers or toes back (small-joint manipulation)
• Kicking or kneeing the head of a grounded opponent, and stomping a grounded opponent
• Spiking an opponent onto their head or neck
• Grabbing the fence or ropes, or holding the opponent's shorts or gloves
• Attacking during a break or after the bell
• Timidity: running away, dropping the mouthguard on purpose, faking an injury

A fighter is grounded when anything other than the soles of their feet is touching the canvas: a knee, a hip, their back. Under the current rules, one hand down isn't enough; it takes both hands. A grounded fighter can still be punched and elbowed, but not kicked or kneed in the head.

The referee can warn the fighter, take away a point (taken off their score for that round), or disqualify them. A fighter hit by a foul can get up to five minutes to recover from a low blow or an eye poke.

If an accidental foul ends the fight early, it's a no contest if it happens before two rounds are done in a three-round fight, or before three are done in a five-round fight. After that, it goes to the scorecards as a technical decision.

Under the Unified Rules. Pick one.