Yes, Wolfsbane is actually considered very poisonous. While the Wolfsbane flowers are used in the Harry Potter universe to make potions and medicines, even in the magical world, Wolfsbane leaves are highly poisonous and can cause severe effects if swallowed or sometimes even touched. In the Herbology classes, Professor Sprout is said to have taken extreme caution by wearing dragon hide gloves to touch Aconite. Aconite roots, if used properly are not considered poisonous and are sometimes used in potions too.