About 50% of all drugs originate from plants and animals, especially from higher plants. The production of plant drugs often has to overcome several obstacles. The Division of Pharmacognosy of the Center for Bio-Pharmaceutical Sciences is involved in developing biotechnological production methods that may help to avoid such problems. In the research field of plant cell biotechnology there is a close co-operation with Delft. University of Technology. As an example some studies on tissue and suspension cultures ofCinchona species and on the biosynthesis ofCinchona alkaloids are described.