India has a very strong tradition of use of natural materials as drugs. The oldest written records of an even ancient oral tradition, namely the Vedas, mention the virtues of several hundreds of herbs. Many herbs and minerals used in Ayurveda since centuries earlier were later described in written form by ancient herbalists such as Charaka and Sushruta during the first millennium BC. The Sushruta Samhita attributed to Sushruta in the 6th century BC describes 700 medicinal plants, 64 preparations from mineral sources and 57 preparations based on animal sources. Likewise the Charaka Samhita (1500–400 AD) provides an exhaustive description of around 600 plants with information on methods of collecting plants, classifying, combining, processing, their applications in specific stages and conditions, incompatibilities, contra-indications and information regarding poisons. There are approximately 1,800 botanical species mentioned in the classical Ayurvedic literature and around 8,000 species in folklore literature.

Ayurveda has a unique way of understanding plants. Unlike in western science, plant classification and nomenclature serve different purposes. The nomenclature of Ayurveda is not the binomial system that has been adopted by modern botany. Many names refer to a single plant and single name is used to denote many plants. A particular plant species may have a group of synonyms ranging from 1 to 50. Each of these names focuses on a special aspect of the plant and thus provides a comprehensive picture of the various aspects of the plant including its morphology, ecological factors, therapeutic parts, seasonal characters, qualities, biological actions and uses. This naming system was primarily designed to help a physician select a plant for medicinal purposes rather than to establish its taxonomical character. Thus plant nomenclature used in Ayurveda is a therapeutic nomenclature, based on a polynomial system of naming. Dravyaguna vijnana is the special branch of Ayurveda that elaborates the qualities and biological actions of several natural products of human consumption. Root (moola), bark (valcra), heart wood (koshti), secretions (niryasaha), stalk (naalika), extracted juice (ras), tender leaves (mrdu patra), alkali (ksharaha), latex (niryasa), fruit (phalam), flower (pushpam), ash (bhasma), oil (taila), thorn (kantaka), leaves (patra), leaf buds (patra-mukula), tubers (kandaha), sprouts (ankuraha), pedicle (manjari), petals (dalam), stamen (pankesara), seed (beejam) and whole plant (gulma) are the plant parts used in Ayurveda.

There are a good number of classic medical texts and manuscripts that deal with plants. These are largely treatises, compendiums, lexicons, critical commentaries and texts on specific areas like pharmacy, paediatrics, etc. Apart from major treatises like Charaka Samhita, Sushruta Samhita and Ashtanga Hridaya written before 1st century BC, several other treatises dating back to before this period include Harita Samhita, Bhela Samhita, Kashyap Samhita, which are not available in complete form. During medieval period or between the 8th and 15th century there have been many works written in the field of Ayurvedic pharmacology or ‘dravya guna’ (quality of drugs) as it is called in Sanskrit. A good number of nighantus were coined during this period. These were appendices to the ancient samhitas and contained synonyms, qualities of drugs and the condition in which they are to be used. Vyakhyas are critical commentaries on treatises and also carry elaborate references to plants.

The vast literature reserve thus indicates that the understanding of natural resources in the traditional pharmacopoeia had been quite dynamic. This knowledge was updated from time to time with the addition of newer drugs and removal of obscure ones. For example, rare drugs such as soma with supposedly celestial powers mentioned in the Sushruta Samhita were later dropped by Vagbhata, the author of Ashtanga Hridaya (600 AD) possibly because of non-availability of plants due to difficulties in accessing them. Plants whose therapeutic properties were newly identified were incorporated. There has been a gradual increase in the number of plants starting from Rig Veda to the nighantus. A number of drugs were introduced from other parts of the world through trade and foreign contacts. For instance spices, aromatics and other drugs like Hingu (asafoetida), Kesar (saffron) and Madhuka (licorice) were imported. Exotic plants like brinjal, green chillies, potato, tapioca, pineapple, tea and coffee have been studied based on Ayurvedic parameters and incorporated into literature only in the last few centuries.

Also Indian alchemy was well ahead of its times with the usage of mercury, sulphur, mica, arsenic, magnetic iron, antimony, zinc, iron pyrites and ferrous sulphate being used for medicinal purpose. A range of natural products apart from plants and minerals including exotic animal products made out of human skull, animal bones, bodily secretions, horns, hides, etc. were used in the amelioration of ailments both in humans and animals.