Improved Toughness( Complete Warrior, p. 101)
[Fighter Bonus Feat, General]
You are signifi cantly tougher than normal.
Base Fortitude save bonus +2,
You gain a number of hit points equal to your current Hit Dice. Each time you gain a HD (such as by gaining a level), you gain 1 additional hit point. If you lose a HD (such as by losing a level), you lose 1 hit point permanently.
A fighter may select Improved Toughness as one of his fighter bonus feats.