Poison has always been a problem for hunters. The forests are full of venomous creatures, just waiting for a chance to strike. The difference between an edible mushroom and one filled with deadly toxins, is hard to spot on a moonless night. Thus the antipoison potion was once of the first to be created. A glorious catch-all that fought against all the venoms and toxins of the realm.
They’re also surprisingly good for a hangover.