Feats

Improved Trip [General]

Prerequisites: Int 13, Combat Expertise.

Benefit: You do not provoke an attack of opportunity when you attempt to trip an opponent while you are unarmed. You also gain a +4 bonus on your Strength check to trip your opponent.

If you trip an opponent in melee combat, you immediately get a melee attack against that opponent as if you hadn't used your attack for the trip attempt.

Normal: Without this feat, you provoke an attack of opportunity when you attempt to trip an opponent while you are unarmed.

Special: At 6th level, a monk may select Improved Trip as a bonus feat, even if she does not have the prerequisites.

A fighter may select Improved Trip as one of his fighter bonus feats.

Source: SRD 3.5 Feats