The formation of daodi medicinal materials.

Daodi medicinal material is produced and assembled in specific geographic regions with designated natural conditions and ecological environment, with particular attention to cultivation technique, harvesting and processing. The quality and clinical effects surpass those of same botanical origin produced from other regions. It is thus widely recognized and has long enjoyed a good reputation. Based on literature, market and field investigation on daodi medicinal materials, the historical background and reasons behind the formation and the development of daodi medicinal material are analyzed. This review clarifies the concept and rationalizes the formation of daodi medicinal material.