The immune system of the Pokémon prevents it from getting poisoned. If a poisoned Pokémon has Immunity as its original Ability but not its current Ability, it will remain poisoned when switched out.If the Pokémon with this Ability is poisoned and is holding a Pecha or Lum Berry, the Berry will be eaten and cure the Pokémon of poison before Immunity has a chance to activate.A Pokémon with Immunity can be poisoned by Sunsteel Strike if the attacker has Poison Touch, but will be cured of poison immediately.
When a Pokémon with this Ability is knocked out by an opponent's attack, it deals damage to that opponent equal to the amount of HP it had left before last being hit. If a Pokémon with this Ability faints through Future Sight or Doom Desire, Innards Out will only activate if the user of the move is still on the field. If a Pokémon with this Ability moves first and is then knocked out by Core Enforcer, Innards Out will not activate. If Innards Out causes two opposing Pokemon to faint at the same time, and neither party has any remaining Pokémon, then the Pokémon that activated Innards Out loses.
Insomnia prevents the Pokémon from being afflicted by sleep and Yawnn. Rest will fail when used by the Pokémon. A Pokémon with this Ability will wake up if it is asleep in battle (such as if it gains the Ability outside of battle or by an effect like Skill Swap, or is put to sleep by a Pokémon with an Ability like Mold Breaker).
When a sleeping Pokémon with Insomnia enters battle, it will be cured of sleep. If a sleeping Pokémon has Insomnia as its original Ability but not its current Ability, it will remain asleep when switched out. If the Pokémon with this Ability is asleep and is holding a Chesto or Lum Berry, the Berry will be eaten and cure the Pokémon of sleep before Insomnia has a chance to activate.
Natural Cure heals any status conditions upon switching out or completing a battle (if it was in battle at the end of the battle).
This effect will occur if Natural Cure is the Pokémon's Ability in battle when it switches out and is not suppressed; a Pokémon that obtained the Ability with Trace will have its status condition cured when it switches out, whereas a Pokémon which has Natural Cure but has been affected by Gastro Acid will not.