At least 90% of medicinal and aromatic plants (MAP) of the European market originate from natural resources, what represents the loss of about 20.000 to 30.000 tons of raw materials annually. Excessive utilization of wild MAP from natural habitats, and environmental degradation due to human activities are the main reasons why MAP are often considered as endangered in many European regions. Conservation programs on medicinal and aromatic plants (MAP) aimed at conservation of natural heredity, at improvement of the biological knowledge as well as of the safe use of MAP should be urged in EU countries. Inventory and monitoring of endangered MAP species and their ex situ maintenance are important parts of the national programs. Preparation of relevant descriptors (based on morphological characteristics, chemo-taxonomy and end-product quality requirements) and successive evaluation of ecotypes of MAP will accelerate the selection and breeding work/cultivar development. Examples of the use of the inventory data in planning field cultivation of MAP are presented. Also, proposals for descriptors of MAP, that have been elaborated on the basis of experimental work in Slovenia, are reviewed.