Ayurveda (ayur-veda, life-knowledge') the science of health, was regarded as one of the Upavedas, closely associated with the Atharva-veda. It embraces all aspects of well­being, physical, mental and to some extent spiritual, its main object being ayus, long life, and arogya, diseaselessness. In practice it covers the study of cause, symptoms, diagnosis and cure of disease.

Ayurveda was largely confined to what was known as chikitsa, lore, or know-how, specifically the medical lore of the chikitsa, 'one who knows', or the vaidya, 'knowing' person, i.e. the physician or general practitioner. Chikitsa was defined as the treatment of roga (diseases).

Hindu tradition itself derives the science of medicine from Brahma who instituted it in order to allay the pains and tribulations of the gods and lesser beings. His work conceived in 100,000 verses describing the cause (hetu), symptoms (linga) and remedy (aushadha) of all diseases was handed down to a line of gods and rishi custodians. From Brahma it passed to prajapati, then to Daksha, the Ashvins (the divine Physicians), Indra, Bhaskara (the Sungod, Dhanvantari Physician of the gods, Harita and Kshirapani. Several of these are mythical figures, but with the next three names, Charaka, Susruta and Vagbhata, known as the vriddha-trayi,' The Triad of the Ancients', the history of Indian medicine may be.

Charaka's work is of a highly ethical order and remarkably Hippocratic in content, and most of the rules governing the conduct of the Hindu physician are taken from him. The manual contains chapters on a variety of subjects such as longevity, drugs, prescriptions, ointments and many kinds of purgatives.

Sushruta wrote a work on medicine in eight sthanas or parts and also a thesis on the therapeutic properties of garlic. His sharirasthana is succinct and systematic, and very ably reduces to manageable size the vast amount of data that Indian Medical Science had inherited.

The study of medicine and healing, was referred to as ashtanga, 'eight limbed', after the number of subjects into which it was traditionally divided. The list of subjects vary and today run into dozen of headings. The recognized limbs or subjects are generally

1. chikitsa, the lore of the Physician, the sphere of the general practitioner
2. Shalya or Surgery
3. deha-vritti, 'body-activity', anatomy and physiology
4. nidana or diagnoses
5. dravya-vidya, 'substance science', a knowledge of material medica, medicines and pharmacology
6. agadatantra, 'antidote-study' i.e. toxicology, the study of visha or poisons and their antidotes
7. stri-tantra, 'female study', a knowledge of female diseases and psychology
8. pashu-vidya, animal-knowledge, veterinary science
9. kaumara-bhritya 'youth-fostering' pediatrics, the treatment of children's diseases
10. urdhvanga, 'upper-part, 'the treatment of diseases of the eye, ear, nose, throat, teeth and mouth
11. bhuta-vidya, 'demonology', the study of the demonological and occult causes of disease and their cure
12. rasavada, 'elixir-doctrine' or alchemy, and vaji-karana, 'stallion maping,' the study of aphrodisiacs.

In its origins Ayurveda was mainly magical and empiric, but in the course of time it developed a philosophical theory, highly elaborated, abstruse and remote from reality, based on recondite abstractions that had little apparent relevance to practical therapy. Much of the commonly employed therapy was based on the principle of ushman, that is the notion of hot and cold diseases and their treatment by opposites. Disorders (vyadhi) of the doshas or humours were treated by medicines of a contrary nature that is those containing a large proportion of their opposite qualities. 'When a particular ingredient of the body is increased or diminished to abnormal proportion, it should be reduced or restored to its normal measure'. The material medica used by the Hindus covered a vast number of specifics to deal with all such contingencies.