Rite of Bodily Purity

You energize your body’s immune system, improving your ability to resist toxins and ailments. You gain a +2 resistance bonus on saving throws to resist diseases, drugs, and poisons. Additionally, at any time during the spell’s duration, whenever you fail a saving throw to resist a disease, drug, or poison, you can expend the spell’s remaining duration as an immediate action in order to reroll that saving throw. You must take the second result, even if it’s worse. The +2 resistance bonus granted by the spell applies to the reroll, but after you make this reroll, the spell ends.