The authors first review different factors that affect the chemical composition of essential oils such as chemotype, ecotype, phenology, organ type and extraction method. Cichorium sp., Cynara sp., Helianthus sp., Taraxacum sp. and Lactuca sp are widely used by the general population in the forms of teas and infusions, as well as in direct contact with wounds. In order to potentiate the action of these plants and direct these compounds to their place of action, this collection reviews some strategies that have been developed to direct these compounds to their place of action. Next, the authors present information established from available scientific literature discussing the ethnopharmacological, biologicaland phytochemical activities of some important endemic medicinal species from Asteraceae family growing in Algerian Sahara namely: Anvillea radiata Coss, Brocchia cinerea, Bubonium graveolens, Launaea arborescens and Warionia saharae. The concluding chapter focuses on the endemic and rare species of the Asteraceae family in the southern Iberian Peninsula. Its global floristic contingent includes a large number of genera and species that are distributed throughout a wide range of environments from sea level to Mediterranean high mountains on all substrate types.