Being one of the panchamahabhoota, agni (fire) has the characteristic that it cannot exist without a base. In the body it exists in pitta dosha.
Agni is responsible for the following functions:
Digestion - indigestion (Pakti- Apakti)
Vision- absence of vision (Darshanam- Adarshanam)
Degree of heat (Matra- Amatratvamushmanala)
Normal -abnormal complexion (Prakrit - Vikarit varnam)
Prowess- fear (Shaurya- Bhaya)
Anger - exholoration (krodham- Harsham)
Confusion- clarity of mind (Moha- Prasadan)
For the metabolic processes in the body, there are three main groups of biological factors, probably exhibiting enzymatic functions (agnis).
Jatharagni or Koshthagni:
Present in the pachak pitta. It is responsible for the digestion and the absorption of nutritious substances during this process.
The process of digestion (ahar pachan) is divided in three stages, which collectively is called awastha paka and can be divided in the following.
Amavstha (Madhuravastha) Paka - in stomach
Pachymanavastha (Amlavstha) Paka - in 'grahani' (Duodenum)
Pakavstha (Katuavstha) Paka - in small and large intestine
As the rasa changes in different phase of digestion these phase of digestion are called avsthapaka. At the end of the digestion the digested food have their original rasa which is in accordance with the rasa of the ingested food. This is called as Nistha paka .It is also called popularly as Vipaka.
Madhur rasa & Lavan rasa have Madhura Vipaka, Amla rasa have amla vipaka and Katu, Tikta & Kashaya rasa have Katu vipaka.
In ayurveda it is believed that everything is made up of five elements and so is the body. These five elements are the panchmahabhoota and are responsible for constituting every living being in the world. Agni transforms the Asharir Mahabhoota (external mahabhoot) to Sharir Mahabhoota. Example - When we drink water Jala Mahabhoota (water) dominates and later the water is transformed by Jala Mahabhoota agni to the Sharir Jala Containing five types of biological factors, it is responsible for the processing of the five basic elements into a composition useful to the body.
Dhatvagnis : The third group contains seven types, each for the assimilation of the seven tissues This assimilation takes place successively. From the absorbed nutritious substance, plasma (rasa) is produced first; from plasma, blood (rakta) is formed, then muscular tissue (mamsa), adipose tissue (meda), bony tissue (asthi), bone marrow (majjan) and the reproductive cells (shukra).
Besides performing all the metabolic functions agni takes care of digestion (ahar pachan) and in the absence of ahar it acts on the ama pachan i.e. properly metabolize the improper metabolites. When ahar and ama are absence Agni does the function of dhatu i.e. rasa, rakta etc. Digestion of dhatu is a fatal condition in which dhatus are broken down to get energy. The reduction or deficiency of the quantum of dhatu in the human body leads to the disease called 'Kshaya roga'.
In ayurveda it is believed that all the pathology occurs due to the impairment in Agni (Kaya). Hence the correction of Kaya i.e. Agni is called the treatment or 'Kaya Chikitsa' in ayurveda
Agnis are also classified into four categories according to how they manifest in the human being:
Mandagni - mild,
Vishamagni - irregular, and
Samagni - regular or Balanced.
About The Author
Dr.Shashikant Patwardhan is practicing as 'Ayurvedic Consultant' for last 25 years at the city -Sangli , Maharashtra -India. He has done his graduation in Ayurvedic Medicine and Surgery [B.A.M&S] and post graduate Fellowship of Faculty of Ayurvedic Medicine [F.F.A.M.] From Tilak Ayurved Mahavidyalaya, Pune University , India, during the years 1970-1976. He is a chief editor and Ayurvedic Consultant of a 'Comprehensive website on Ayurveda'. He is an author of many books on Ayurveda and is first to publish them in ebook format.Up till now he has written four ebooks - 1. Ayurvedic Cure of Diabetes 2. Home Remedies in Ayurveda 3. Treat Common Diseases with Ayurveda & Yoga and 4. Ayurvedic Principles Revealed He regularly writes articles on various topics in Ayurveda in Ayurvedic health magazines and alternative medicine sites.