The identity and the motive of the shoe-thrower aren't clear. He's believed to be an Iraqi.
Al-Zeidi's brother, Maithan chased the attacker into the audience and pelted him with a shoe as he left the room.
Muntadhar al-Zeidi is a TV reporter who drew international attention when he hurled his shoes at President Bush during a Baghdad news conference in 2008.
He was arrested by security guards, and imprisoned for nine months before he was released in September.
His action made him a hero to many opponents of the Iraq war.
AP contributed to this report.