Agni is the biological fire that governs the process of metabolism in the body. It powers the transformation of one substance into another. Agni encompasses all the changes in the body and mind from the dense to the subtler. Agni is found in the alimentary canal and digests food. The main function of Agni is the promotion of process of digestion. Therefore, the digestive abilities are related to the strength of Agni. Maximum number of diseases is directly or indirectly related to the improper functioning of Agni. It is responsible for neutralizing toxins, bacteria and viruses that hinders with the functioning of immune system.

Types Of Agni
There are around thirteen forms of Agni in the body that are responsible for digestion. The most important is jatharagni that works at the gastrointestinal level and the main function is to separate the nutrients and waste from the ingested food.

There are other twelve agni- dhatagnis that are seven in number and the bhutagnis that are five in number. These twelve agnis are related to the dhatus and the panchamahabhootas.

The seven dhatagnis metabolizes and regulates the physiological processes of the seven dhatus. It is a biochemical process that includes the anabolic and catabolic activities of the body.

The five bhutagnis metabolizes the panchamahabhootas present in the dhatus of the body. The bhutagnis are a form of heat that is always present in tissues and is responsible for the proper functioning and development of the tissues. They also help in the regulation of digestion and assimilation of the panchamahabhootas present in the ingested food.

Another Classification
Agnis are further classified into four categories depending on the way of their manifestation in the human beings.

Tiksnagni (sharp) : It is produced by the pitta dosha. The people with excess of tiksnagni are more prone towards inflammation and acidity. It implies strong digestion, circulation and immunity. In case of excess of tiksnagni impurities gets accumulated in the rasa and rakta dhatus.

Mandagni (mild) : It is produced by the kapha dosha. In people with mandagni there is slow circulation and excess of secretions are formed. It shows symptoms like slow digestion, low appetite, cravings for heavy or sweet foods and a tendency to carry excess body weight.

Visamagni (irregular) : It is produced by vata dosha. People with visamagni often have intestinal bloating, gastritis, constipation and abdominal disorders. It also weakens the immune system with regard to nervous system, bones and upper respiratory tract. It can promote irregular appetite, with intense periods of hunger alternating with lack of interest in food.

Samagni (regular and balanced) : It is produces by the normal digestion of the three doshas. It usually occurs in individuals who are well balanced; eat balanced diet, rest and exercise sufficiently. People with samagni have normal appetite, satisfaction, normal bowel movements and emotional stability.

Therefore, a balanced Agni is vital for good health. In every tissue and cell Agni is present and is necessary for maintaining the nutrition and autoimmune mechanism. Healthy Agni results in good digestion process, proper elimination, proper tissue formation, strong immune system, high energy levels, good circulation and pleasant body odour and breath.