Plants are the source of many important pharmaceuticals. Especially plants rich in secondary metabolites are of interest. These metabolites have been subjected to natural selection during evolution when the presence of particular secondary metabolite conferred an advantage to the species. The secondary metabolites are thought to be benecial for the plant itself as a physiological active compound, as stress-protecting agents, and by their role in plant resistance against pests and diseases. In addition, some of these secondary metabolites have a benecial impact on the human health. A main issue related to human health is to optimize the production of the valuable secondary plant metabolites. Considerable effort has been done to generate such metabolites in plant cell or tissue culture. Nevertheless, collection from wild and agricultural production of medical plants still remains the most important supply for plant-derived pharmaceuticals. However, harvesting from wild, especially for species with a high demand, can cause loss of genetic diversity and habitat destruction due to overharvesting. The agricultural cultivation of medicinal plants is an interesting alternative and offers several advantages: reliable botanical identication, less genetic, phenotypic, and phytochemical diversity, availability of well-dened cultivars adapted to the requirements of the stakeholders, better guarantee for appropriate conservation, less extract variability and instability, and a steadier source of raw material.