Not only are you immune to disease, like most paladins, but you also are highly resilient to poisons.
Prerequisites: Divine health class feature.
Pathfinder Roleplaying Game: Ultimate Magic. © 2011, Paizo Publishing, LLC; Authors: Jason Bulmahn, Tim Hitchcock, Colin McComb, Rob McCreary, Jason Nelson, Stephen Radney-MacFarland, Sean K Reynolds, Owen K.C. Stephens, and Russ Taylor.