Resist Poison( Forgotten Realms Campaign Setting, p. 37)
Over years, some among your people carefully expose themselves to poisons in controlled dosages in order to build up immunity to their* effects. A few are thereby weakened, but the strong adjust. Regions: Gray dwarf, half-orc, orc.
You get a +4 bonus on Fortitude saving throws against poison.
You may only take this feat as a 1st-level character.