The word Ayurveda derived from AYU and VEDA. AYU means life VEDA means science or knowledge. Ayurveda means the science of life. Charaka defines "That science is designated as Ayurveda which deals with advantage and disadvantage as well as happy and unhappy states of life along with what is good and bad for life, its measurement and the life itself (Charaka Sutra 1 - 4)" Ayurveda embraces all living things, animate and inanimate. It is divided into three main branches viz., Nara Ayurveda dealing with human life, Satva Ayurveda the science dealing with animal life and its diseases, Vriksha Ayurveda the science dealing with plant life, its growth and diseases. It is amply clear that Ayurveda is not only a system of medicine but also a way of life for complete positive health and spiritual attainments.
Ayurveda believes that positive health is the basis for attaining four cherished goals of life (chaturvidh purushartha) viz., Dharma, Artha, Kama, Moksha. All these four goals cannot be achieved without sound positive health.
Positive health is defined as
(a) Dosha Dhatu samya (well balanced metabolism)
(b) Prasanna Atma, Indriya, Manah (happy state of the soul, senses and the mind). Senses here mean the five organs of perception Gyanendriya viz., smell, taste, sight, touch, and hearing coupled with the organs of action - Karmendriya viz., mouth, hands, foot and organs of excretion and reproduction.