Growl will lower the opponent's Attack by 1 step (termed BTLs in the Gameboy description) on the Stat growth scale.
Growl will always fail if it has already been used 6 times on the same pokemon, without a move that raises Attack being used by or against the pokemon affected by Growl. This is due to the fact that a stat may only be lowered by a maximum of 6 steps, until it is reset by the use of Haze or the pokemon is switched out normally. The maximum is the limit of how many decreases can be applied to a stat. If another move decreases the Attack stat of the pokemon that Growl is used against, the number of steps that it decreases the Attack stat by will count toward the 6 step limit, and reduce the number of times that Growl can be used appropriately.
Growl is affected by Brightpowder when the opposing pokémon is equipped with it.
Like all other non-damaging Normal-type attacks, Growl affects Ghost-type pokémon, despite their immunity to Normal attacks.
