Dungwort
From Absit Omen Lexicon
Dungwort, also called Stinking Hellebore, is found wild in many parts of England. Despite its it's name, it doesn't actually smell all that bad until you crush the leaves.
In the wizarding world, it is usually used as an ingredient in poisons or mind-altering potions.
It is also a key stank ingredient in Figaro's Smoke Bombs.
