Once during your turn (before your attack), you may flip a coin. If heads, your opponent's Active Pokémon is now Asleep. If tails, your Active Pokémon is now Asleep.
If this Pokémon is your Active Pokémon and is damaged by an opponent's attack (even if this Pokémon is Knocked Out), the Attacking Pokémon is now Poisoned.
If this Pokémon is your Active Pokémon and is damaged by an opponent's attack (even if this Pokémon is Knocked Out), this Attacking Pokémon is now Poisoned.