The White Herb is a type of held item. It is an in-battle effect item that restores all of the holder's decreased stats. If the stat stages of any of the holder's stats are negative, it consumes the White Herb and all negative stat stages are reset to be neutral.
If a multi-strike move activates Tangling Hair, Gooey, or Weak Armor, a Pokémon will not consume the White Herb until after the final strike. If a Pokémon holding a White Herb activates multiple Pokémon's Tangling Hair or Gooey, it will not consume its White Herb until all of the Abilities have activated for that attack.
If a Pokémon with Weak Armor is hit by Knock Off, Thief, Covet, or a physical move from a Pokémon with Magician, its held White Herb will be knocked off or stolen before it has a chance to activate. If a Pokémon with Weak Armor is hit by Fling using a White Herb, the White Herb's effect will be applied before Weak Armor lowers its Defense. If a Pokémon uses a contact move that lowers its own stats (such as Superpower) on a Pokémon with Pickpocket, its held White Herb will be stolen before it has a chance to activate.
If the Pokémon with Defiant or Competitive is holding a White Herb, Defiant or Competitive will trigger before the White Herb, so the user will receive the Attack or Special Attack boost and then the lowered stat will be restored; if the same stat boosted by the Ability is lowered, the White Herb never has a chance to activate.
If a Pokémon with Contrary has one of its stats lowered by an O-Power, its held White Herb will not be activated until after a Pokémon uses a move.