Vials of Mysterious Liquid are bottles of a corrosive substance used to contaminate iron ore across the Sword Coast in Baldur's Gate. It is found on the bodies of kobolds in the Nashkel Mines. This item has no use. It is part of The Tainted Ore quest, which was cut from the game and can only be restored by installing the mod Unfinished Business by Pocket Plane. Drinking it as a potion will cause the imbiber to become poisoned as well as permanently lose one point of Constitution.