Fire lichen was a type of lichen that grew in the Underdark near sources of geothermal heat. It was recognizable by its stalks of pale orange-white. When ground to powder and fermented, it formed a paste that was very spicy but edible, added to soups and stews or spread on Bluecap sporebread for flavor.
Dark Dwarves were known to ferment fire lichen into an fiercely hot liquor.