Cryptostictic acid is a chemical compound of the depsidone class.

It has the molecular formula C19H16O9 and is a secondary metabolite of various lichens.

It was first reported in 1980 as a constituent of Lobaria oregana.

[1] It has since been identified in lichens in the genera Ramalina,[2] Oxneriaria,[3] and Usnea,[4] among others.