Ayurveda is an Upaveda of Atharva or Rigveda according to some schools or is a Panchama Veda. It is also considered as Upanga of Atharva Veda i.e. it is not imposed or added from the exterior but is a part and parcel of the main body of the Vedas. It is evident from the above that the Vedas are the original sources of the subject matter of Ayurveda.
According to Atharva Veda
Brahma puri navadwara devanama pooh ayodhyapuri hiranmayakosho deepah. The word Purusha is defined in this way. One who resides in pura is called Purusha. Imperishable Atma and perishable Panchabhautik body are the two main constituents of the Purusha.
Similarly, description of physiological concepts
Tridhatu i.e. Tridosha and Sapta Dhatus, five divisions of Vayu, or its twin forms are also mentioned in the Vedas succinctly or by name clearly— Ye Tri-saptah (Atharvaveda), Prnaya Swana apanaya Swaha etc. (Yajurveda), Tri Dhatu
Seven dhatus are also mentioned in a covert and overt manner as Sapta sayas staying in the body and also categorically as Twacha, Lohita, Mamsa, Asthi, Majja and Shukra.
Tridoshas and seven dhatus are mentioned as supporting agents of all living creatures in the mantra “Ye Tri Saptah Vishwa Roopani Bibhratah” of the Atharvaveda and Sayan the commentator explains them as Tridosha and Sapta Dhatus. Both the Samhitas, Charaka and Sushruta have also called them Dhatus.
Concept of Sharira (body)
Concept of body configurations which are condemnable was originally mentioned in Yajurveda.
Regarding the four constituents of Purusha, the first and most obvious factor is Shareera or Deha. Its description is given in Samhitas under two heads—structures and functions. Twacha, Loma, Lohita, Mamsa, Asthi, Majja and Shukra i.e. seven dhatus are mentioned clearly in Yajurveda; and Sheersha, bahu, uroo, pada, nabhi, hridaya, kloma, yakrit, pleeha, basti, vanisthu, matasna, antrani, puritat, chakshu, shrotra, mukha etc. organs, limbs and viscera too are referred in Purushasukta and other contexts. Prana, Vak, sravana, darshana, swapna, jagarana, etc. functions are also mentioned briefly in the Vedas.
The second component of purusha is indriyas. They are located in shareera at specific sites (adhishthana) and are invisible and only are inferred by their respective functions. The buddhindriyas- shrotra, chakshu, twacha etc. and karmendriyas- pada, hasta, payu, vak, upastha, are also mentioned in connection with ashwamedha, pashumedha, and purushamedha.
The third component of purusha, manas, is still more subtle than the two inert ones referred above and is the instrument of Atma to communicate with the outer world, indriyas and body and to conceive the ideas of the past and future. Its dimensions and functions are poetically given in “Shiv sankalpa sukta” of Yajurveda.
The fourth component is Atma. It is described to be all-pervasive and one that enters into a physical body to take the form of a living creature; it is not different from the one that is universal, both are one and the same. This is described in the course of sarvamedha.
These examples are sufficient to show that the basic concepts of Ayurveda are mentioned in the mantras of Vedas. They were developed in successive phases of Brahmana and Upanishad eras not separately but during discussions on processes of yajna or philosophical topics. However, they were discussed in detail and systematically arranged in the post-Upanishad period or samhita period of Ayurveda.
Yakshma (denotes general diseases and specifically a disease characterized by consumption), Takma (Fevers), Kasa (cough), Harima (Jaundice), Kilasa, Shwitras, sidhma etc. affecting the skin (varieties of Kushtha etc.) are diseases of physique; Unmada, Apriatipada, Amati, Durmati, etc. are diseases of the psyche; asu (vandhya-infertility), Atiskadvari (pradara-excessive discharge red and white), Palikni (grey hairs) vijarjara (laxity of the body tissues) etc., diseases of reproductive organs of women; and kleeba (impotent, the sexual debility in male) etc. disease are referred in Yajurveda.