References to diseases, herbs and herbal cures can be seen in all the four Vedas. Atharvana Veda has many hymns eulogizing herbs. Aushadhi Sukta in Rig Veda is the oldest document available on medicinal plants in this region. Ayurvedic teachings were originally transmitted for thousands of years before being written down in melodious Sanskrit poetry. Ayurveda in its first recorded form is specifically called Atharvana Veda. The earliest scripts were written on palm and betula leaves. Being perishable the scripts were later written on stone and copper sheets (Table 2.1).

The depth of medical knowledge possessed by Ayurveda is reflected in the large number of medical manuscripts and the range of subjects they cover. Apart from knowledge of drugs, there is extensive coverage of diagnostic methods, therapeutic techniques, surgery, specialized lines of treatment, physiological concepts as well as an understanding of the mind-body relationships.

Figure 2.1 The lineage of Ayurveda

This knowledge today lies scattered in several ancient manuscripts in oriental libraries and in private custody not only in India, but also in Sri Lanka, Nepal, Burma, Mangolia, China and Thailand as well as in the libraries of Western Europe and the United States. These are largely Samhitas (treatises), Samgrahas (compendiums), Nighantus (lexicons), Vyakhyas (critical commentaries) and texts on specific areas like pharmacy, paediatrics etc.