Frangula azorica V. Grubow (Rhamnaceae), locally known as “sanguinho”, is an Azorean endemism inscribed on the IUCN Red List of Threatened Species. Morphological, chemical and biological studies on F. azorica are scarce, but preliminary studies on the bark of this species enable the identification of anthraquinone derivatives as major compounds of this plant part. This kind of compounds are present and responsible for the laxative activity of Frangulae cortex and Rhamni purshianae cortex, two well known herbal drugs of the Western Pharmacopoeias belonging to the same botanical familly (Rhamnaceae).