From the Story
Discovered in Book 3, Chapter 18, Moony, Wormtail, Padfoot and Prongs
"Wolfsbane Potion is a relatively recent discovery that allows werewolves to remain safe during the full moon. A complex potion, it must be drunk during the week preceding a full moon. The potion allows the werewolf to keep their human mind after the transformation, so they are able to wait for the moon to wane as a harmless wolf.