An overview is given of the current position of medicinal herbs in general
in relation to usage, market and production, types of pharmacological activ
ity and how they differ from conventional drugs. The increasing importance
of quality and manufactured products is also discussed. A more detailed con
sideration of these issues is given in relation to echinacea, valerian and
St John's wort as these herbs are well studied, are market leaders and have
widespread community usage.