How and why should we standardize phytopharmaceutical drugs for clinical validation?

Standardized extracts are needed to carry out reliable clinical trials. The standardization of an extract does not include only a whole of analytical controls: it requires also a thorough description of the starting drug and of the whole extraction process, both basic items for the constancy of the quality of an extract. Another not minor aspect in the standardization of an extract is its nomenclature which must include all the necessary data for a clear definition (drug, physical state, solvent of extraction, composition) of the extract itself. Two examples of standardization are described, one concerning an extract whose therapeutical active constituents are known (anthocyanoside complex of Vaccinium myrtillus) and the other concerning an extract whose constituents must be regarded as chemical markers (Pygeum africamum extract).