A unique approach to the characterization and standardization of feverfew (Tanacetum parthenium) leaf materials and their preparations is proposed. Authenticated leaf materials from parthenolide-rich chemotypes associated with positive clinical outcomes, as well as material from parthenolide-free chemotypes, will be subjected to characterization, using physicochemical characteristics and phenotypic (morphological and microscopic) features. A set of combined relevant data derived from these studies will be established as criteria for the selection of leaf materials to be used for all subsequent studies. The preliminary physicochemical profiles of different materials and their preparations will be used to validate efficiency and reproducibility of extraction methods to be developed. The highly characterized and reproducible extracts prepared using these validated methods will be used as test materials for further intensive physicochemical studies, as well as for bioassay and gene expression studies for the correlation and prediction of anti-migraine activity of feverfew materials in Phase II. PROPOSED COMMERCIAL APPLICATION: To identify genotypic plant materials and appropriate quality control tests to facilitate consistent agricultural production of feverfew raw material. To provide a substantial (less arbitrary) basis for botanical and chemical standardization of feverfew leaf and extract preparations.