Wra'sh Blood (3.5e Feat)
From D&D Wiki
You lived in the Dark Woods and Dead marsh for most of your life, it poison infected your veins. You are now very resistant to poison and diseases.
Wra'sh Blood [Regional]
Resistance to poison and disease; immunity to some diseases
Prerequisite: Native to an area of heavy marshlands
Benefit: You gain +2 to Fortitude save vs. poisons and diseases. You are immune to any diseases or poisons with DC lower than 21.