Stictic acid is a ß-orcinol depsidone found in a broad range of lichen species. Stictic acid was first isolated and reported by Knop and Schnedermann in 1846, then later isolated as scopularic acid by Zopf in 1907. In the 1930s Asahina and co-workers and Curd and Robertson independently recognised the synonymy. Stictic acid is an important standard in the chemotaxonomy of lichens. Stictic acid exhibits a broad range of pharmacology and has been reported to have antioxidant, antimicrobial, insect anti-feedant and antitumor activities.