The central concept of Ayurveda is the theory that health exists when there is a balance between three fundamental bodily humours or doshas called Vata, Pitta and Kapha.
Vata is the air principle necessary to mobilize the function of the nervous system.
Pitta is the fire principle which uses bile to direct digestion and hence metabolism into the venous system.
Kapha is the water principle which relates to mucous, lubrication and the carrier of nutrients into the arterial system.
In Ayurvedic philosophy, the five elements combine in pairs to form three dynamic forces or interactions called doshas. Dosha means "fault or that which changes." It is a word derived from the root dus, which is equivalent to the English prefix 'dys', such as in dysfunction, dystrophy, etc. In this sense, dosha can be regarded as a fault, mistake, error, or a transgression against the cosmic rhythm.
The doshic barometers are constantly moving in dynamic balance, one with the others. Doshas are required for the life to happen. In Ayurveda, dosha is also known as the governing principles as every living thing in nature is characterized by the dosha.