Ayurveda views the health of the body as the functioning of a biological fire governing metabolism. It is called agni. Agni is not simply a symbol for the power of digestion. In the broader sense, it is the creative flame that works behind all life, building up the entire universe as a stage by stage unfoldment of itself, which, thereby, contains within itself the key to all transformations.
Agni is present not only in human beings but in all nature. It has a special abode in plants, which contain the agni of photosynthesis.
When agni is strong, food is digested properly, toxins of various kinds, largely from undigested food particles, (Called ama in Ayurveda), accumulate and breed disease.
Plants contain agni, through which they digest sunlight and produce life. Herbs can transmit their agni to us, their capacity to digest and transform, and this may augment our own power of digestion, or give us the capacity to digest substances we normally cannot. The agni of plants can feed our agni. Through this interconnection, we join ourselves with the cosmic agni, the creative force of life and healing.
The agni from plants is magnetically attracted by its opposite nature to the negative life-force of the ama, or various toxic accumulations in our body. The result is their neutralization and a restoration of harmony.
Herbs can be used to supplement agni and thereby restore our autoimmune system. This restores the power of our aura, which is nothing more than the glow of our agni. By their very nature the right herbs and spices can feed agni, directly strengthening the basic energy of body-mind, allowing for the right digestion, not only of food but also experience.