It is a secondary metabolite produced by a variety of lichens.

Fumarprotocetraric acid is mainly known for its occurrence in Iceland moss (Cetraria islandica), where it is present in a mass fraction of 1–2% (dried thallus).

[2] In addition, fumarprotocetraric acid has been detected in many other lichens, including: Fumarprotocetraric acid has antibacterial activity.

[1] It also induces an immunostimulating effect in vitro by triggering the formation of hydrogen peroxide.

[1] Furthermore, cytotoxicity against two cancer cell lines has been demonstrated.