A survey of known and of recently isolated constituents from Ginkgo leaves is given. The structures of flavonoids and terpene lactones which are considered to be the active compounds as well as their qualitative and quantitative determination in Ginkgo leaves and phytomedicines are presented. In the case of flavonoid analysis three selective methods worked out in our laboratories are described. The quality control of terpene lactones is discussed on the basis of a recently published paper. Finally, the standardization methods used for the quality control of Ginkgo preparations as well as the question as to whether or not phytomedicine generics -so called “phytogenerics“ - exist, is discussed.