If the holder is hit by a damaging move and does not faint, it consumes the Red Card and forces the Pokémon that used the move (even if it was an ally) to switch to a random Pokémon. If held by a wild Pokémon in a Single Battle, it forces a player's Pokémon that attacks it to flee when activated. In a wild battle that was initiated as a Horde Encounter or Double Battle, or an SOS Battle in which there are currently two wild Pokémon, the Red Card will cause the player's attacking Pokémon to switch rather than flee. If multiple Pokémon, each holding a Red Card, are hit by a single attack, only the fastest holder's held Red Card will activate.
The Red Card will not activate if the attacker is a wild Pokémon or its Trainer has no Pokémon to switch in, even if the Red Card would cause the attacker to flee rather than switch out. The Red Card will not activate if a Pokémon's substitute takes the hit instead. If a move is affected by the effect of Sheer Force, that move will not activate the Red Card. The Red Card activates after the last strike of a multi-strike move.
If the attacker has Suction Cups or is under the effect of Ingrain, the Red Card will still activate and be consumed, but fails to cause that Pokémon to switch out or flee (even if that attacker is Ghost-type, has the Ability Run Away, or is holding a Shed Shell or Smoke Ball). Trapping moves and Abilities, other than Ingrain, do not prevent a Pokémon from being forced to switch out or flee by the Red Card.
The Red Card will be knocked off or stolen by Knock Off, Thief, Covet, or Magician before it has the opportunity to activate. A Pokémon with Pickpocket holding a Red Card can steal an attacker's item with Pickpocket even after that attacker is switched out by the Pokémon's held Red Card; if a Pokémon steals a Red Card due to Pickpocket, that Red Card cannot activate for that same attack. The Red Card switches out the attacker before its own held Life Orb has the chance to damage it, so that attacker does not take damage from it. If a Pokémon holding a Red Card is hit by Dragon Tail or Circle Throw, it is forced to switch out or flee before its held Red Card has the opportunity to activate. If a Pokémon holding a Red Card is hit by U-turn or Volt Switch, the Red Card activates before the attacker is switched out by the move. Emergency Exit and Wimp Out activate after a Pokémon is switched in by Red Card.