Improved Unarmed Strike

Base attack bonus +1.

You are proficient with your unarmed strike, which deals lethal or nonlethal damage (at your option) equal to 1d6 + your Strength modifier (1d4 + your Strength modifier if you are Small). Your unarmed strikes count as armed, which means that opponents do not get attacks of opportunity when you attack them unarmed, and you threaten squares and may make attacks of opportunity even while unarmed.

Note that your unarmed strike is a natural weapon, even with this feat. You cannot make iterative attacks with a natural weapon. When making attack with a weapon, you can use your unarmed strike as a secondary natural attack with a -5 penalty to the attack roll, as normal for natural weapons.

A monk gains Improved Unarmed Strike as a bonus feat at 1st level and gains additional benefits with an unarmed strike.

Without this feat, you deal only 1d3 points of nonlethal damage (if Medium size). Unarmed strikes normally provoke attacks of opportunity, and unarmed combatants normally cannot make attacks of opportunity.