Different conditions may lend themselves to different styles. Convenience may be a valid reason for choosing one method over another. Herbal Preparations Whole or Bulk Herbs Plant parts may be dried by different techniques, with or without preservatives. In addition to being used in the production of herbal products, whole plants may be used for infusion or decoction. Quality of whole plants varies with growing conditions, including location, weather conditions, maturity at time of collection, technique of drying, and storage conditions, among other factors.
Location can affect plant potency.
Feverfew grown in England was shown to be active against migraine headache, while analysis of plants grown in America revealed absence of parthenolide, believed to be the active compound. It is believed to work in a way similar to methysergide, the active ingredient of the migraine medication Sansert. Plant recognition is a complex science, but some plants have distinctive characteristics which ease recognition. For instance, Valerian, used for sleep, has a characteristic odor, described as similar to dirty socks. Apparently, rats find the smell attractive, and legend says that the Pied Piper used Valerian to lure the rats from Hamlin.