Fumarprotocetraric acid is a ß-orcinol depsidone found in a broad range of lichen species, notably within the genera, Usnea, Parmelia and Cladonia. Fumarprotocetraric acid is an important standard in the chemotaxonomy of lichens. Isolated reports of antibacterial activity occur in the literature, however unlike other lichen acids, the pharmacology and use in other applications has received little attention.