Traditional systems of medicine make use of a wide spectrum of natural resources as part of their pharmacopoeia. It is beyond the scope of this book to examine all the various systems and their use of these resources. But it is important to know how the resources are studied, the history of their use and the general principles by which they are incorporated into the respective pharmacopoeias. Significantly, the estimated 50,000 herbal formulations documented in Indian medical texts and used for a wide range of health conditions are about 10 times more than the 4,000-odd modern drugs that represent the sum total of the world's pharmacopoeia.

In this section, we focus on the importance given to medicinal plants and the concepts used to understand them as pharmaceutical material. Much of the information included here is drawn from Ayurveda and this will suffice to give an indication of how traditional systems work. However, in this context it is important to remember that each system is unique and based on differing principles. It is not always possible to apply generalisations drawn from Ayurvedic principles to all Indian traditional systems of medicine (local health tradition methodologies are quite distinct and will be examined in a subsequent chapter).

The use of plants for medicinal purposes has a very long and unbroken history in the Indian subcontinent. The Ausadhi sukta in the Rig Veda is the oldest document available on medicinal plants in this region.