Agni is the invariable agent in the process of Paka (digestion, transformation). Ingested food is to be digested, absorbed and assimilated, which is unavoidable for the maintenance of life, and is performed by the Agni. Different examples are available in our classics to indicate that Pitta is the same as Agni, but some doubt arises behind this concept, that Pitta is Agni. Agni is innumerable because of its presence in each and every paramanu of the body. But, the enumeration of the number of Agni varies in various classical Ayurvedic texts. According to the functions and site of action, Agni has been divided into 13 types, i.e. one Jatharagni, five Bhutagni and seven Dhatvagni. Jatharagni is the most important one, which digests four types of food and transforms it into Rasa and Mala. The five Bhutagnis act on the respective bhutika portion of the food and thereby nourish the Bhutas in the body. The seven Dhatvagni act on the respective dhatus by which each Dhatu is broken into three parts. In this way, the entire process of transformation consists of two types of products - PRasad (essence) and Kitta (excrete). The former is taken for nourishment while the latter one is thrown out, which otherwise defiles the body if it stays longer.
Keywords: Agni; Pitta; bhutagni; dhatvagni; jatharagni.