Pokémon Ruby Version, Sapphire Version, and Emerald Version - Descriptions of Common Effects
Effects that are common to many attacks are described below. Of the effects listed here, a Pokémon will remain poisoned, burned, paralysis, frozen, and asleep even when the Pokémon leaves the battle, including when a battle ends. (However, a Pokémon will stop being poisoned, burned, paralyzed, frozen, and asleep, as well as have full HP and PP, when it’s taken to a Pokémon Center nurse or placed in a PC storage box.) An effect can’t cause poison, burn, paralysis, freezing, or sleep against a Pokémon if it already has one of these five conditions or if it has fainted.
Burn (BRN)
If a Pokémon is burned, the damage from physical attacks it uses is halved, and it loses 1/8 of its maximum HP (but not less than 1 HP) at the end of each turn. Fire-type Pokémon can’t become burned by any means.
Poison (PSN)
If a Pokémon is poisoned, it loses 1/8 of its maximum HP (but not less than 1 HP) at the end of each turn. Poison- and Steel-type Pokémon can’t become poisoned by any means . Outside of battle, a poisoned Pokémon loses 1 HP every four steps the player walks.
Being badly poisoned differs from normal poisoning in the HP loss method during battle. When a Pokémon becomes badly poisoned or a badly poisoned Pokémon enters the battle, a variable, T, is set to 0 for that Pokémon’s position. At the end of each turn, if the Pokémon is badly poisoned, T rises by 1 (up to a maximum of 15) and the Pokémon loses its maximum HP, divided by 16 and multiplied by T (but not less than 1 HP). (This HP loss happens instead of the HP loss for regular poisoning.) "Being badly poisoned doesn’t revert to normal poisoning by any means, even when a battle ends.
Unless otherwise noted, poison includes being normally poisoned and badly poisoned.
Paralysis (PAR)
If a Pokémon is paralyzed, its Speed is multiplied by 1/4 (see Priority ) and there is a 1/4 chance that it will be unable to attack during its attack segment. Ground-type Pokémon can’t become paralyzed by Electric type attacks, but can be paralyzed by all other means .
Sleep (SLP)
If a Pokémon is asleep, it can’t attack during its attack segment. When a Pokémon falls asleep, it receives a sleep count of 2 to 7. At the beginning of the Pokémon’s attack segment, its sleep count is reduced by 1, and then it wakes up if the sleep count is 0 or less. The game stores the current duration of a Pokémon that’s asleep, in case the Pokémon leaves battle and enters the battle in another one.
Frozen (FRZ)
If a Pokémon is frozen, it can’t attack during its attack segment. Ice-type Pokémon can’t become frozen by any means . At the beginning of the Pokémon’s attack segment, it will thaw out at a 20% chance. If the Pokémon loses HP because of a Fire-type attack (not just those that cause burns; Hidden Power is considered as Normal) , it thaws out.
Confusion
When a Pokémon becomes confused, it receives a count of 2 to 5. At the beginning of the Pokémon’s attack segment, this count is reduced by 1, then if it is greater than 0, there is a 50% chance that the Pokémon will deal damage to itself rather than use an attack. The self-inflicted confusion attack is a Normal-type physical attack, has a power of 40, can’t be a critical hit, and ignores the effects of Reflect and Helping Hand, and its damage isn’t affected by the Pokémon’s types. Confusion is removed from the Pokémon when it leaves the battle (except Baton Pass).
Flinch
After a Pokémon uses a move that makes the target flinch in the same turn, the target can flinch when the beginning of its attack segment comes and thus skip its attack this turn. Effects that cause a Pokémon to flinch set a flag on that Pokémon. If the flag is set as the Pokémon begins its attack segment, it will flinch. This flag is cleared at the beginning of a Pokémon’s attack segment and at the end of each turn.