Alchemist's fire was liquid that stuck to most everything it touched, so named due to its common production by Alchemists rather than any relation to true Alchemy. Upon contact with air, it burst into flames and burns until consumed or put out. Because of this, the liquid was frequently stored in breakable flasks, where it could be used as a thrown weapon or in traps.
A creature with alchemist's fire adhered to its body could avoid additional injury if they managed to extinguish the flames before they dissipated naturally. Rolling on the ground improved the chances, while immersion in water put the flames out immediately.